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JOURNAL  OF  THE  SOCIETY  OF 
MOTION   PICTURE   ENGINEERS 

VOLUME  XLI  •         •          •  JULY,  1943 

CONTENTS 

PAGE 
Motion  Picture  Standards  in  Wartime     D.  E.  HYNDMAN       3 

The  Removal  of  Hypo  and  Silver  Salts  from  Photographic 
Materials   as   Affected  by  the  Composition  of   the 
Processing  Solutions 
J.  I.  CRABTREE,  G.  T.  EATON,  AND  L.  E.  MUEHLER        9 

Effect  of  High-Intensity  Arcs  upon  35-Mm  Film  Projec- 
tion 

E.  K.  CARVER,  R.  H.  TALBOT,  AND  H.  A.  LOOMIS       69 

Film  Distortions  and  Their  Effect  upon  Projection  Quality 

E.  K.  CARVER,  R.  H.  TALBOT,  AND  H.  A.  LOOMIS      88 

Carbon  Arc  Projection  of  16-Mm  Film         W.  C.  KALB       94 

The  Practical  Side  of  Direct  16-Mm  Laboratory  Work 

L.  THOMPSON     101 

Society  Announcements  119 

(The  Society  is  not  responsible  for  statements  of  authors.) 


JOURNAL  OF  THE  SOCIETY  OF 
MOTION. PICTURE  ENGINEERS 

SYLVAN  HARRIS,  EDITOR 
ARTHUR  C.  DOWNES,  Chairman 

Board  of  Editors 

JOHN  I.  CRABTREE      ALFRED  N.  GOLDSMITH       EDWARD  W.  KELLOGG 
CLYDE  R.  KEITH       ALAN  M.  GUNDELFINGER     CHARLES  W.  HANDLEY 

ARTHUR  C.  HARDY 
Officers  of  the  Society 
** President:  HERBERT  GRIFFIN, 

90  Gold  Street,  New  York,  N.  Y. 
**  Past-President:  EMERY  HUSB, 

6706  Santa  Monica  Blvd.,  Hollywood,  Calif. 
**  Executive  Vice-President:  LOREN  L.  RYDER, 
5451  Marathon  Street,  Hollywood,  Calif. 
*Engineering  Vice-President:  DONALD  E.  HYNDMAN, 

350  Madison  Avenue,  New  York,  N.  Y. 
** Editorial  Vice-President:  ARTHUR  C.  DOWNES, 

Box  6087,  Cleveland,  Ohio. 
*  Financial  Vice-President:  ARTHUR  S.  DICKINSON, 

28  W.  44th  Street,  New  York,  N.  Y. 
** Convention  Vice-President:  WILLIAM  C.  KUNZMANN, 

Box  6087,  Cleveland,  Ohio. 
^Secretary:  E.  ALLAN  WILLIFORD, 

30  E.  42nd  Street,  New  York,  N.  Y. 
^Treasurer:  M.  R.  BOYER, 

350  Fifth  Ave.,  New  York,  N.  Y. 
Governors 

*H.  D.  BRADBURY,  411  Fifth  Avenue,  New  York,  N.  Y. 
*FRANK  E.  CARLSON,  Nela  Park,  Cleveland,  Ohio. 
*ALFRED  N.  GOLDSMITH,  580  Fifth  Avenue,  New  York,  N.  Y. 
*A.  M.  GUNDELFINGER,  2800  S.  Olive  St.,  Burbank,  Calif. 
*CHARLES  W.  HANDLEY,  1960  W.  84th  Street,  Los  Angeles,  Calif 
*EDWARD  M.  HONAN,  6601  Romaine  Street,  Hollywood,  Calif. 
*JOHN  A.  MAURER,  117  E.  24th  Street,  New  York,  N.  Y. 
**WILLIAM  A.  MUELLER,  Burbank,  Calif. 

*HOLLIS  W.  MOYSE,  6656  Santa  Monica  Blvd.,  Hollywood,  Calif. 
**H.  W.  REMERSHIED,  716  N.  La  Brea  St.,  Hollywood,  Calif. 
"JOSEPH  H.  SPRAY,  1277  E.  14th  Street,  Brooklyn,  N.  Y. 
**REEVE  O.  STROCK,  195  Broadway,  New  York,  N.  Y. 

*Term  expires  December  31,  1943. 
**Term  expires  December  31,  1944. 


Subscription  to  non-members,  $8.00  per  annum;  to  members,  $5.00  per  annum,  included 
in  their  annual  membership  dues;  single  copies,  $1.00.  A  discount  on  subscription  or  single 
copies  of  15  per  cent  is  allowed  to  accredited  agencies.  Order  from  the  Society  of  Motion 
Picture  Engineers,  Inc.,  20th  and  Northampton  Sts.,  Easton,  Pa.,  or  Hotel  Pennsylvania,  New 
York,  N.  Y. 

Published  monthly  at  Easton,  Pa.,  by  the  Society  of  Motion  Picture  Engineers. 

Publication  Office,  20th  &  Northampton  Sts.,  Easton,  Pa. 

General  and  Editorial  Office,  Hotel  Pennsylvania,  New  York,  N.  Y. 

Entered  as  second-class  matter  January  15,  1930,  at  the  Post  Office  at  Easton, 

Pa.,  under  the  Act  of  March  3,  1879.     Copyrighted,  1943,  by  the  Society  of  Motiou 

Picture  Engineers,  Inc. 


MOTION  PICTURE  STANDARDS  IN  WARTIME* 
DONALD  E.  HYNDMAN** 

An  American  bomber  is  zooming  its  way  to  enemy  territory  on  an 
important  mission  of  destruction.  It  reaches  the  outskirts  of  its 
destination,  loses  altitude,  the  bomb-bay  doors  are  opened.  The 
bombardier  sights  his  target,  the  bombs  are  released.  The  photog- 
rapher aims  his  motion  picture  camera  as  the  bombs  fall  and  presses 
the  release  lever — it  starts — groans  and  stops — dead.  The  bomber 
returns  to  base  with  no  photographic  record  to  show  whether  a  "hit" 
or  a  "miss"  was  made.  Why  did  the  camera  fail?  Was  the  diameter 
of  the  sprockets  too  great  or  too  small?  Was  the  film  perforated 
under-  or  over-pitch  for  the  sprockets?  Was  the  film  core  binding 
on  the  spindle  because  it  was  too  wide?  Was  the  failure  caused  by 
non-interchangeability  of  parts  and  materials? 

Of  course,  such  an  incident  did  not  occur  because  standards  were 
employed  in  manufacturing  the  camera,  accessories,  and  film. 
Standards  avoid  such  dangers.  Standards  provide  interchange- 
ability,  simplification  of  groups  of  articles,  economies  in  manufacture, 
agreement  between  purchaser  and  purveyor  on  specifications,  and 
avoid  entanglements  and  misunderstandings. 

To  avoid  misconception  and  to  acquaint  the  uninitiated,  it  seems 
best  that  definitions  of  the  terms  and  concise  descriptions  of  the 
methods  employed  in  standardization  procedure  be  given  as  an  in- 
troduction to  Motion  Picture  Standards.  The  following  definition 
of  an  SMPE  Recommended  Practice  has  been  approved  by  the 
Board  of  Governors  and  the  Standards  Committee  of  the  Society  of 
Motion  Picture  Engineers.  The  following  definition  of  an  American 
Standard  has  been  approved  by  the  executive-secretary  of  the 
American  Standards  Association. 

SMPE  Recommended  Practice. — An  SMPE  Recommended  Practice  is  a  de- 
scription of  a  recommended  process,  method,  construction,  or  device  intended  to 
accomplish  a  specific  and  desired  aim.  This  issuance  of  such  a  Recommended 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  Engineering  Vice-President  of  the  Society. 


4  D.  E.  HYNDMAN  [j.  s.  M.  P.  E. 

Practice  indicates  that  it  is  acceptable  to  the  Standards  Committee  and  to  the 
Board  of  Governors  of  the  Society  of  Motion  Picture  Engineers.  Its  publication 
by  the  SMPE  constitutes  a  recommendation  to  interested  parties  that  it  be 
utilized  as  a  habitual  procedure,  an\i  that  comments  or  criticisms  concerning  its 
effectiveness  in  practice  are  welcomed  and  will  be  considered. 

American  Standard. — American  Standard  is  a  form  of  approval  given  by  the 
American  Standards  Association  to  specifications,  safety  codes,  methods  of  test, 
definitions,  abbreviations,  and  the  like.  Its  adoption  and  publication  by  the 
authorization  of  the  American  Standards  Association  recommend  to  interested 
parties  that  it  be  accepted  as  a  standard  in  industry,  commerce,  and  elsewhere 
because  it  is  believed  to  be  technically,  scientifically,  and  industrially  effective 
and  acceptable.  An  American  Standard,  having  been  approved  according  to  a 
prescribed  democratic  procedure  by  a  nationally  recognized  body  of  technical 
and  scientific  experts  or  specialists  drawn  from  engineering  organizations,  in- 
dustry, the  government,  consumers,  and  other  legitimately  interested  groups,  will 
normally  receive  full  approval  and  acceptance  in  practice  by  a  wide  group  of  users. 

Under  the  heading  of  Specifications  would  be  included  tables  of  dimensions 
with  tolerances  necessary  to  insure  interchangeability  in  quantity  production  as 
well  as  requirements  of  a  chemical,  physical,  or  metallurgical  nature  necessary  to 
insure  a  quality.  Specifications,  of  course,  may  also  include  a  definite  and 
specific  method  of  test. 

The  general  standardization  procedure  is  based  upon  the  demo- 
cratic method  that  a  proposal,  to  become  an  SMPE  Recommended 
Practice  or  American  Standard,  may  be  originated  or  proposed  either 
singly  or  collectively  by  any  interested  person,  group,  commercial 
organization,  or  scientific,  technical,  or  engineering  society,  etc. 

A  proposal  when  submitted  to  the  SMPE  is  referred  to  the  Stand- 
ards Committee.  This  committee  is  composed  of  authoritative  en- 
gineers and  technicians  of  the  motion  picture  industry,  representing 
producers,  distributors,  exhibitors,  and  manufacturers  of  all  types  of 
equipment  utilized  in  the  industry.  The  Committee  follows  a  very 
specific  procedure  prescribed  by  the  Administrative  Practices  of  the 
Society.  The  Committee  carefully  studies  the  proposal,  prepares 
the  necessary  forms,  and  requests  written  comment  from  interested 
parties  before  deciding  whether  the  proposal  should  be  classified  for 
consideration  as  an  SMPE  Recommended  Practice  or  for  submission 
to  the  American  Standards  Association  recommending  its  considera- 
tion for  an  American  Standard. 

Following  approval  of  the  proposal  by  the  Standards  Committee, 
it  is  submitted  to  the  Board  of  Governors  and,  if  approved,  is  pub- 
lished in  the  JOURNAL  with  an  announcement  of  its  validation  as  an 
SMPE  Recommended  Practice. 

It  is  unlikely,  however,  that  a  proposal  would  not  first  become  an 


July,  1943]      MOTION  PICTURE  STANDARDS  IN  WARTIME  5 

SMPE  Recommended  Practice  before  being  considered  for  or  be- 
coming an  American  Standard  because  as  an  SMPE  Recommended 
Practice  it  constitutes  a  recommendation  to  interested  parties  that 
it  be  utilized  as  a  habitual  procedure  and  that  comments  or  criticisms 
concerning  its  effectiveness  in  practice  are  welcome  and  will  be  con- 
sidered. This  procedure  gives  all  interested  parties  ample  time  to 
try  thoroughly  the  recommendation  before  it  is  advanced  to  the 
higher  status  of  a  standard. 

When  a  proposal,  whether  it  be  merely  a  new  project  or  an  SMPE 
Recommended  Practice,  is  submitted  to  the  ASA  for  consideration 
as  an  American  Standard,  it  is  referred  to  the  Sectional  Committee 
on  Motion  Pictures,  Z-22.  This  Sectional  Committee,  composed  of 
representative  technical  and  engineering  authorities  from  the  motion 
picture  industry,  representing  producers,  distributors,  exhibitors, 
and  manufacturers  of  all  types  of  motion  picture  equipment,  care- 
fully studies  the  proposal,  arranges  the  form,  and  requests  comments 
from  all  interested  parties.  If  the  project  is  approved,  the  Sec- 
tional Committee  forwards  its  recommendation  to  the  parent  body, 
the  American  Standards  Association.  The  ASA  now  studies  the 
recommendation  of  the  Sectional  Committee  and,  if  approved,  an 
American  Standard  is  issued  with  announcement  of  validation  by 
the  "supreme  court"  of  American  standardization. 

Obviously  many  important  details  are  left  out  of  this  description  of 
the  standardization  procedure,  but  space  permits  mention  of  only 
the  important  features  of  the  process.  An  important  point  is  that 
there  are  no  SMPE  Standards.  Only  SMPE  Recommended  Practices 
exist;  and  only  the  ASA  has  the  right  to  validate  American  Stand- 
ards. There  have  been  no  American  Recommended  Practices 
since  February,  1943. 

Few  persons  realize  the  value  of  standardization  procedures. 
They  may  do  so  subconsciously  in  their  daily  lives  and  tasks  but 
they  do  not  realize  that  the  food  they  eat,  the  clothes  they  wear,  the 
cosmetics,  detergents,  and  the  luxuries  they  buy,  as  well  as  the  tools 
necessary  to  process  and  fabricate  practically  all  the  materials  and 
products,  are  the  results  of  the  work  of  technicians  and  engineers 
who  have  spent  many  days,  weeks,  and  months  on  the  problems  of 
standardizing  both  the  articles  manufactured  and  the  processes  of 
manufacturing  them  so  as  to  assure  consistent-quality  mass-produc- 
tion of  the  things  that  contribute  to  better  living.  Standardization 
speeds  up  production,  refines  individual  and  collective  quality  control, 


6  D.  E.  HYNDMAN  [J.  S.  M.  p.  E. 

maintains  a  consistent  level  and  dispersion  of  quality  and  quantity, 
provides  means  for  rapid  inspection  and  sampling,  produces  normal 
distribution  of  quality  and  quantity,  and  brings  to  the  consumer  a 
uniform  product.  In  addition,  it  promotes  interchangeability  of 
specific  products  serving  the  same  purpose,  allowing  the  consumer 
to  choose  products  on  the  basis  of  quality,  service,  and  utility.  It 
thus  constitutes  an  economic  saving  and  a  major  convenience  to 
producer  and  consumer  alike. 

In  current  circumstances  we  apply  peacetime  knowledge  to  wartime 
practice;  and  when  this  war  is  over,  both  peacetime  and  wartime 
knowledge  will  be  applied  to  postwar  practice.  The  last  war 
necessitated  standardization  to  increase  production,  to  husband  the 
use  of  scarce  materials,  to  .create  new  uses  for  available  substitutes, 
and  to  develop  new  materials  and  new  processes.  These  develop- 
ments did  much  to  provide  better  living  conditions  and  to  bring 
greater  happiness  to  the  people  of  the  world  in  the  quarter-century 
prior  to  the  starting  of  this  war.  Unfortunately,  alien  and  destruc- 
tive forces  partly  annulled  these  gains.  In  the  developments  follow- 
ing the  present  world  conflict  probably  even  greater  improvements 
will  take  place  because  the  speed  of  production  and  efficiency  of  de- 
struction in  this  war  "has  proceeded  at  a  much  greater  rate,  demanding 
more  materials  and  more  accurate  machinery  of  war.  This  demand 
has  forced  a  rapid  development  of  new  materials  as  substitutes  for 
scarce  materials.  Sometimes  the  substitutes  prove  better  in  many 
ways  than  the  original  material.  The  same  will  be  true  in  the 
"postwar"  period. 

Since  Pearl  Harbor,  "War  Model  Standards"  have  been  evolved 
and  put  into  commercial  practice  in  many  fields  of  endeavor.  This 
has  been  rapidly  accomplished  through  the  cooperation  of  industry, 
government  agencies,  such  as  the  War  Production  Board,  Office  of 
Price  Administration,  etc.,  the  technical  and  engineering  societies, 
and  the  American  Standards  Association.  This  cooperation  has 
resulted  in  radical  reductions  in  the  thousands  of  items  produced 
in  some  fields.  It  has  also,  in  many  instances,  brought  about 
simplification  of  models,  utilization  of  substitute  materials,  and 
increased  production  of  fewer  items.  The  effort  has  netted  great 
savings  of  scarce  materials  for  more  important  purposes,  and  has 
efficiently  conserved  both  essential  and  non-vital  goods. 

In  the  electrical  field,  from  approximately  several  hundred  types 
of  electronic  tubes,  capacitors,  volume  controls,  power  transformers, 
chokes,  transformers,  etc.,  the  new  "War  Model  Standards"  have 


July,  1943]      MOTION  PICTURE  STANDARDS  IN  WARTIME  7 

reduced  the  number  of  types  to  approximately  one  to  twenty-five, 
depending  upon  how  readily  interchangeability  can  be  effected. 
The  performance  and  design  standards  provide  for  using  a  minimum 
of  strategic  materials,  but  being  satisfactory  from  an  electrical  and 
service  life  standpoint  to  avoid,  if  possible,  replacing  replacement 
parts.  New  specifications  for  insulators  and  insulating  pieces  cover 
performance  characteristics,  preferred  shapes,  and  interchange- 
ability  for  various  types  of  ceramic  materials  to  assure  the  avail- 
ability of  needed  parts.  Such  standards  are  of  vital  interest  to  the 
motion  picture  industry  as  they  apply  to  electrical  equipment, 
sound  recording  and  reproducing  equipment,  sound  projectors, 
power  supplies  for  studio  lighting  and  theaters,  general  wiring,  etc. 

Many  substitutes  for  strategic  materials  have  been  evolved.  In 
many  types  of  electrical  wiring  installations  copper  wire  is  covered 
with  synthetic  plastic  material  which  serves  as  insulation  in  place 
of  rubber.  A  mixture  of  plastic  and  cotton  cord  provides  material 
to  fabricate  liquid-carrying  hose  in  place  of  the  rubber  and  cord  hose 
formerly  used.  A  number  of  motion  picture  laboratories  are  using 
synthetic  plastic  tubing  to  replace  flexible  rubber  hose  or  hard-rubber 
pipe  for  carrying  photographic  solutions  to  and  from  continuous 
developing  machines.  This  plastic  tubing  can  be  obtained  in  a  wide 
variety  of  wall  thicknesses  and  diameters,  and  it  can  not  only  be  bent 
at  any  angle,  avoiding  the  use  of  elbows,  but  can  also  be  threaded 
for  joints  when  desired,  like  all  hard-rubber  and  metal  pipe.  Plastic 
sheets,  tubes,  and  rods  are  now  finding  utility  where  before  it  was 
believed  only  stainless  steel  or  rubber  could  be  safely  used. 

Such  developments  are  the  results  of  standardization  in  wartime. 
It  must  always  be  the  object  to  effect  interchangeability  of  parts  and 
materials,  to  utilize  substitutes  for  strategic  materials  whenever 
possible,  to  minimize  the  number  of  items  of  any  one  type,  to  specify 
preferred  shapes,  to  maintain  performance  and  life  characteristics 
comparable  to  or  better  than  those  of  the  original  items,  and  to  mini- 
mize replacements. 

There  are  fields  waiting  for  further  enrichment.  Much  can  be 
done  to  standardize  the  equipment  and  procedures  of  motion  picture 
production,  distribution,  and  exhibition.  Improvements  can  be 
made,  with  proper  specification  of  new  materials  and  processes,  that 
will  produce  more  goods  at  lower  cost.  For  instance,  there  is  evi- 
dence that  continuous  developing  machines  and  printers  can  be 
sufficiently  improved  in  design  to  increase  the  footage  output  per 
man-hour  two  to  four-fold,  and  obtain  a  quality  of  product  equivalent 


8  D.  E.  HYNDMAN 

to,  or  even  better  than,  current  products.  Accessory  equipment 
like  manual  and  semi-automatic  rewinds,  hand  and  machine  splicing 
equipment,  cutting  and  editing  equipment,  requires  more  efficient 
design.  A  study  of  the  tooth  shapes  and  diameters  of  all  types  of  feed, 
holdback,  and  intermittent  sprockets  is  essential  to  increasing  the  use- 
ful life  of  motion  picture  film.  This  future  development  demands  and 
warrants  the  attention  of  the  most  competent  engineers  in  the  in- 
dustry. Realization  of  these  goals  would  materially  increase  produc- 
tion, decrease  production  costs,  and  produce  an  even  better  product. 

As  a  note  of  caution,  individualistic  industry  might  misinterpret 
the  purposes  of  standardization.  Standardization  does  not  mean 
that  improvements  are  barred  or  limited;  on  the  contrary,  it  does 
mean  that  only  the  best  is  used.  Only  proved  recommended  changes 
become  formal  standards.  Individual  capable  management  is  still 
the  secret  of  producing  high-quality  products.  Nothing  is  taken 
from  individual  effort  and  ability;  but,  rather,  individual  effort 
and  ability  are  given  better  tools  with  which  to  produce  even  better 
individualistic  products.  Standardization  properly  applied  assures 
present  stabilization  with  enterprise  for  the  future. 

The  motion  picture  industry  faces  not  only  many  problems  that 
are  common  to  other  industries  but  it  has  also  specific  problems  unto 
itself.  The  conservation  of  motion  picture  film  attended  with  the 
conservation  of  all  types  of  materials  that  are  normally  utilized  in 
the  production,  distribution,  and  exhibition  of  motion  pictures, 
necessitates  that  each  and  every  one  connected  with  the  industry 
shall  realize  that  full  cooperation  is  essential  for  maintaining  the  high 
standards  of  entertainment  expected  by  the  public.  The  problems 
are  upon  us.  It  is  in  this  spirit  that  the  technical  committees  of  the 
Society,  on  Cinematography,  Color,  Exchange  Practice,  Laboratory 
Practice,  Non-Theatrical  Equipment,  Preservation  of  Fiim,  Process 
Photography,  Sound,  Standards,  Studio  Lighting,  Television, 
Theater  Engineering,  Projection  Practice,  Theater  Design,  Screen 
Brightness,  and  Theater  Protection  continue  studying  the  pro- 
cedures in  their  respective  fields  to  assist  the  motion  picture  industry 
in  solving  the  technical  conservation  and  procedure  problems  as  they 
arise.  Much  work  has  been  done  and  published  by  these  Com- 
mittees on  recommendations  for  Conservation  of  Film,  Projector 
and  Projection  Room  Design,  Theater  Design,  and  Theater  Pro- 
tection, Investigation  and  study  are  now  in  progress.  Suggestions 
will  be  welcomed  by  these  Committees  and  the  Officers  of  the  Society. 


THE  REMOVAL  OF  HYPO  AND  SILVER  SALTS  FROM 

PHOTOGRAPHIC  MATERIALS  AS  AFFECTED  BY 

THE  COMPOSITION  OF  THE  PROCESSING 

SOLUTIONS* 


J.  I.  CRABTREE,  G.  T.  EATON,  AND  L.  E.  MUEHLER** 


Summary. — During  processing,  if  photographic  materials  are  insufficiently  fixed 
and  washed,  the  silver  thiosulfates  and  sodium  thiosulfate  retained  may  result  in 
staining  of  the  non-image  areas  and  fading  of  the  image  during  subsequent  storage. 
In  the  case  of  films  and  plates  the  thiosulfates  may  be  removed  completely  if  a  judicious 
choice  of  hardening  and  fixing  baths  is  made  and  if  the  most  effective  washing  tech- 
nique is  employed  but,  with  prints,  traces  of  hypo  are  invariably  retained  which  can 
be  removed  by  subsequent  treatment  in  a  peroxide-ammonia  solution. 

Several  factors  contribute  to  the  retention  of  sodium  and  silver  thiosulfates  and  the 
extent  of  this  retention  was  measured  by  careful  determination  of  the  residual  thio- 
sulfate and  silver  in  the  processed  material.  The  hardening  agent,  potassium  alum, 
used  in  hardening  baths  and  fixing  baths  caused  the  greatest  retention  while  chrome 
alum  had  little  effect.  The  accumulation  of  silver  during  exhaustion  of  the  fixing  bath 
resulted  in  retention  of  silver  thiosulfates. 

The  removal  of  sodium  and  silver  thiosulfates  was  aided  by  (1)  use  of  a  second  fixing 
bath  to  remove  silver  and  (if  non-hardening)  to  assist  removal  of  hypo,  (2)  an  increase 
in  the  pH  of  the  fixing  bath  preferably  above  the  isoelectric  point  of  gelatin,  (3)  harden- 
ing prior  to  fixation  as  compared  to  hardening  during  or  after  fixation,  (4)  raising  the 
temperature  of  the  wash  water,  (5)  increasing  the  pH  of  the  wash  water  or  by  the 
use  of  a  dilute  ammonia  solution  near  the  end  of  the  washing  process.  These  treat- 
ments were  less  effective  with  photographic  papers  because  of  the  high  retention  of 
thiosulfates  by  the  paper  base  and  the  baryta  coating.  Processing  recommendations 
to  insure  permanency  during  (a)  archival  and  (b)  normal  periods  of  storage  are 
given. 


INTRODUCTION 

When  a  photographic  film  or  paper  is  insufficiently  washed  during 
processing,  hypo  together  with  silver  thiosulfates  is  retained  and, 
if  the  concentration  is  sufficiently  great  and  the  conditions  of  storage 
are  appropriate,  fading  of  the  image  results.  In  the  case  of  film  with 

*  Presented  at  the  1942  Fall  Meeting  at  New  York;  received  January  8,  1942. 
Communication  No.  862  from  the  Kodak  Research  Laboratories. 
**  Eastman  Kodak  Company,  Rochester,  N.  Y. 

9 


10 


CRABTREE,  EATON,  AND  MUEHLER         [j.  s.  M.  P.  E. 


nitrocellulose  base,  when  exposed  to  high  temperatures,  nitrogen 
oxides  may  be  liberated1  and,  in  the  presence  of  moisture,  the  re- 
sulting nitric  acid  reacts  with  the  silver  image  causing  fading. 

In  this  paper  the  term  "fading"  refers  to  any  change  in  the  density 
or  hue  of  the  silver  image  which  may  or  may  not  be  accompanied 
by  a  staining  in  the  highlights.  The  chief  causes  are:  (a)  sulfiding 
of  the  silver  image  by  the  sulfur  present  in  the  residual  hypo,2  and/or 
(b)  the  decomposition  of  residual  sodium  silver  thiosulfate  complexes 
which  produces  sulfiding  of  the  image  together  with  silver  sulfide 
in  the  highlights. 

The  process  of  fixation  consists  in  the  conversion  of  the  insoluble 
silver  halides  (chloride,  bromide,  or  iodide)  in  the  emulsion  to  soluble 
complex  silver  thiosulfates  and  the  process  of  washing  consists 
in  the  removal  in  solution  of  sodium  thiosulfate  together  with  a 
small  proportion  of  silver  thiosulfates. 

The  ultimate  result  of  incom- 
plete fixation  and/or  incomplete 
washing  is  the  conversion  of  the 
silver  present  in  the  residual  sil- 
ver thiosulfate  to  silver  sulfide 
by  virtue  of  decomposition  of 
the  silver  thiosulfate,  or  by  re- 
action with  hydrogen  sulfide 
present  in  the  atmosphere.  The 
results  of  these  reactions  are 
visible  in  the  dense  area  of  a  film  or  print  by  reflected  light  as  either 
a  yellowish  stain  or  a  metallic  luster  and  in  the  highlights  as  a 
yellowish  to  yellowish  brown  stain  of  silver  sulfide. 

In  any  consideration  of  washing,  therefore,  it  is  important  to 
ascertain  the  concentration  of  both  the  residual  silver  ion  and  thio- 
sulfate ion  and  to  study  the  changes  in  the  proportion  of  the  two  as 
washing  progresses. 

Most  of  the  experiments  outlined  below  were  made  with  motion 
picture  films  but  in  general  the  results  obtained  apply  also  to  other 
photographic  films. 

In  order  to  determine  the  relative  sensitivity  of  motion  picture 
images  to  residual  hypo,  strips  of  various  processed  motion  picture 
negative,  positive,  and  sound-recording  emulsions  on  safety  type 
base,  containing  known  quantities  of  hypo,  were  placed  in  a  sealed 
glass  vessel  which  contained  water,  and  stored  for  several  days  in  an 


FIG.  l. 


Experimental  washing  appa- 
ratus. 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  11 

oven  maintained  at  a  temperature  of  110°F.  The  strips  were  sus- 
pended on  glass  rods  supported  by  glass  frames  and  the  condition 
of  the  film  noted  at  definite  intervals.  These  storage  tests  assisted 
in  the  determination  of  certain  maximum  permissible  hypo  con- 
centrations (sodium  thiosulfate  crystal,  Na2S2O3-5H2O)  with  respect 
to  fading  for  various  types  of  materials.  These  maximum  tolerable 
quantities  were  tentatively  set  at  0.05  milligram  per  square  inch  for 
coarse-grain  negative,  0.01  milligram  per  square-inch  for  positive 
or  fine-grain  positive,  and  0.005  milligram  per  square-inch  for  ex- 
tremely fine-grain  negative  and  positive  films  such  as  Microfile. 
With  concentrations  of  residual  hypo  greater  than  these,  indications 
of  fading,  especially  in  the  halftones,  were  obtained  under  the  ex- 
treme storage  conditions  used. 

The  relationship  between  accelerated  fading  tests  and  normal 
storage  conditions  has  not  been  precisely  determined.  However, 
negative  and  positive  motion  picture  films  which  have  been  stored 
at  Kodak  Park3  for  at  least  ten  years  at  55°F  and  70  per  cent  relative 
humidity  and  which  contained  quantities  of  hypo  of  the  order  of 
that  in  present-day  commercially  processed  emulsions  have  not 
shown  signs  of  visible  fading.  A  period  of  one  day  in  the  accelerated 
test  would  therefore  appear  to  be  equivalent  to  a  period  of  not  less 
than  ten  years  at  a  temperature  of  55°F  and  70  per  cent  relative 
humidity.  For  shorter  times  of  keeping  greater  quantities  of  hypo 
than  those  stipulated  may  be  tolerated. 

In  this  connection  it  is  of  interest  to  know  the  approximate  hypo 
and  silver  contents  of  some  films  and  papers  processed  commercially. 
Many  samples  of  films  and  prints  from  various  sources  have  been 
tested  during  the  past  few  years  for  hypo  and  silver  content  and  the 
results  shown  in  Table  I  indicate  the  existence  of  a  wide  variation 
in  hypo  content.  In  general  the  residual  silver  content  was  very 
low. 

With  the  present  trend  toward  the  use  of  fine-grain  emulsions  for 
sound  recording  and  projection  print  purposes,  and  the  increasing 
use  of  fine-grain  Microfile  film  for  archival  storage,  it  is  of  increasing 
importance  that  the  hypo  be  removed  from  films  as  completely  as 
possible  during  processing. 

To  date,  although  laboratory  technicians  have  realized  the  im- 
portance of  thorough  washing  it  has  been  generally  considered  that 
the  most  important  factors  which  influence  the  removal  of  silver 
and  thiosulfate  compounds  are  (a)  time  of  washing,  and  (b)  rate 


12  CRABTREE,  EATON,  AND  MUEHLER         [j.  s.  M.  P.  E. 

of  renewal  of  the  water.     The  effect  of  the  nature  of  the  processing 
solutions  has  been  given  little  consideration. 

TABLE  I 

Average  Hypo  and  Silver  Contents  of  Some  Commercially  Processed  Negatives  and 

Prints 

Film  Hypo  (Mg  per  Sq-In)  Silver 

Motion  picture  negative  Nil     ->0.18  Nil  —*-  Trace 

Motion  picture  positive  Nil     -*•  0.18  Nil  — »•  Trace 

Photofinishers 

(a)  Machine  processed  0.35  — »•  0.50*  About  0.01  mg  per  sq-in 

(b)  Hand  processed  0. 10-*  0.15*  Nil 
*-ray  0.35  -*  0.50*                             Trace 

Paper 

Single  weight 

(a)     Machine  processed  0.15-»-0.35                                Trace 

(6)     Hand  processed  0. 10-*  0.20                                Trace 

Double  weight  0 . 25  -»•  0 . 45  Trace-0 . 01  mg  per  sq-in 

*  These  films  are  coated  on  both  sides  and  the  data  represent  the  concentrations 
of  hypo  in  only  one  of  the  coatings.  When  the  hypo  content  was  determined  by 
the  mercuric  chloride  test,  the  total  hypo  content  was  measured  and  was,  in  each 
case,  twice  the  value  given. 

Data  in  the  literature  regarding  the  effect  of  the  composition  of 
the  processing  baths  on  hypo  removal  are  sparse  and  generally  in- 
conclusive. As  early  as  1900  Gaedicke4  stated  that  alum-hardened 
plates  required  excessive  washing  compared  with  non-hardened 
plates.  In  1917  Liippo-Cramer,5  commenting  on  Elsden's6  use  of 
neutral  thiosulfate,  reported  that  a  highly  acid  non-hardening  fixing 
bath  washed  out  more  slowly  than  plain  thiosulfate.  Hickman 
and  Spencer7  in  1924  attempted  to  show  the  effect  of  hardening  agents 
and  modified  fixing  baths  on  the  washing  of  plates.  They  in- 
vestigated the  use  of  alum  and  formaldehyde  between  the  developer 
and  fixing  bath  and  the  use  of  alum  in  the  fixing  bath.  Formaldehyde 
had  no  effect  on  the  time  of  washing,  while  immersion  in  a  5  per 
cent  alum  bath  with  adequate  washing  before  and  after  "profoundly 
influenced  the  retention  of  electrolyte."  When  alum  was  used  in  a 
fixing  bath  maintained  sufficiently  acid  to  prevent  subsequent  hy- 
drolysis, there  was  no  difficulty  in  removing  hypo  or  other  electrolyte. 
In  view  of  this  apparent  uncertain  effect  of  alums  on  washing,  it 
was  considered  desirable  to  make  an  extensive  investigation  involving 
various  types  of  present-day  processing  solutions  in  order  to  deter 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  13 

mine  the  effect  on  hypo  and  silver  removal  of  the  use  of  various 
developers,  stop  baths,  fixing  baths,  and  supplementary  treatments, 
and  especially  the  effect  of  the  presence  of  hardeners  in  the  fixing 
bath,  variations  in  the  pH  of  the  bath,  the  time  of  fixation,  and 
the  effectiveness  of  the  subsequent  washing  procedure. 

METHOD 

At  the  outset  it  was  realized  that  careful  control  of  the  various 
factors  involved  would  not  be  obtained  by  the  use  of  trays  or  large 
tanks,  but  a  series  of  flat  spiral  reel  outfits  in  use  for  the  daylight 
processing  of  35-mm  films  proved  satisfactory  and  permitted  adequate 
reproducibility  of  results. 

One-foot  lengths  of  the  film  were  developed  in  500  cc  of  the  recom- 
mended developer,  drained  for  10  seconds,  rinsed  10  seconds  in  run- 
ning water,  hardened  and  fixed  for  four  times  the  apparent  "time 
to  clear"  (see  p.  25)  in  a  500-cc  volume  of  the  bath,  drained  10 
seconds,  and  finally  washed  in  an  experimental  washing  apparatus 
designed  to  give  a  very  rapid  change  of  water  and  a  high  degree  of 
agitation  as  shown  in  Fig.  1.  All  the  processing  solutions  and  the 
wash  water  were  maintained  at  a  temperature  of  68°F  and  uniform 
agitation  was  used  throughout. 

The  water,  which  overflowed  at  B,  was  introduced  through  A 
into  the  2-liter  circular  tank  C  at  a  controlled  flow  such  that  the 
outflow  was  55  times  the  capacity  of  the  vessel  each  hour.  The 
agitation  produced  by  the  water  influx  was  increased  greatly  by  the 
use  of  a  high-speed  electric  stirrer  D  having  a  slightly  fluted  convex 
disk  for  the  stirring  propeller.  Samples  of  the  processed  film  were 
mounted  on  a  wooden  rack  E  held  in  position  in  the  tank.  These 
conditions  were  such  that  high-speed  negative  films  fixed  in  fresh 
baths,  washed  completely  in  40  minutes  following  the  most  in- 
hibitive  treatment  with  respect  to  the  removal  of  hypo.  With 
positive  films  the  flow  was  reduced  to  12  gallons  per  hour  or  about 
two-fifths  that  used  for  negative  film. 

The  majority  of  the  tests  were  made  with  Eastman  Motion  Picture 
Super- J£Jf  Panchromatic  Negative  Film,  Type  1232,  but  tests  were 
also  made  with  the  following  Eastman  Motion  Picture  Films: 

Plus-Z  Panchromatic  Negative  Film,  Type  1231. 
Background  Panchromatic  Negative  Film,  Type  1213. 
Fine-Grain  Panchromatic  Duplicating  Negative  Film,  Type  1203. 
Release  Positive  Film,  Type  1301. 


14  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 

High  Contrast  Positive  Film,  Type  1363. 
Fine-Grain  Duplicating  Positive  Film,  Type  1365. 
Sound  Recording  Film,  Type  1357. 

In  addition,  tests  were  made  with  Microfile,  Type  5204,  and  paper 
prints. 

Melting-point  determinations  were  made  on  each  sample  of 
processed  film  to  determine  whether  or  not  the  degree  of  hardening 
was  seriously  affected  by  modifications  of  the  fixing  and  hardening 
bath  formulas. 

The  quantity  of  hypo  retained  by  all  the  processed  film  samples 
was  determined  by  the  mercuric  chloride-potassium  bromide  method 
of  Crabtree  and  Ross8  in  which  one  square-inch  of  film  is  placed 
in  a  10-cc  volume  of  the  reagent*  and  the  resultant  turbidity  com- 
pared with  a  series  of  standard  turbidities.  The  latter  are  produced 
by  the  addition  of  measured  volumes  of  a  1:10,000  solution  of  hypo 
to  the  10-cc  volume  of  the  reagent. 

Note:  The  fact  that  the  total  residual  hypo  in  a  film  sample  is 
accurately  measured  by  the  mercuric  chloride  reagent  has  been 
verified  by  two  confirmatory  tests:  (1)  when  the  film  was  washed 
just  enough  to  give  a  negative  test  with  mercuric  chloride,  a  negative 
test  was  obtained  with  an  excess  of  1  per  cent  acidified  silver  nitrate 
solution  which  reacts  with  all  the  hypo  in  situ,  and  (2)  when  one- 
half  of  a  film  sample  was  soaked  in  water  to  equilibrium  and  the 
solution  tested  with  mercuric  chloride,  an  identical  value  was  ob- 
tained as  by  direct  determination  on  the  other  half  of  the  film  sample. 

The  quantity  of  hypo  retained  by  prints  was  determined  by 
bathing  the  print  sample  in  a  1  per  cent  (acidified)  silver  nitrate 
solution,  reacting  the  excess  silver  nitrate  with  sodium  chloride, 
fixing  out  the  silver  chloride  with  hypo  solution,  and  then  determin- 
ing the  transmission  density  of  the  silver  sulfide  stain.  The  cor- 
responding quantity  of  hypo  was  read  from  a  standard  curve. 

The  relative  quantities  of  silver  retained  by  the  processed  film 
samples  were  determined  by  the  sodium  sulfide  spot  test  in  which  a 
drop  of  0.2  per  cent  sodium  sulfide  solution  containing  1  cc  of  40 
per  cent  formalin  per  100  cc  was  placed  on  the  film  for  5  minutes 
and  then  removed  with  absorbent  paper.  The  relative  quantities 
were  recorded  as  density  readings  (D  =  log  l/T)  obtained  by  measur- 
ing the  percentage  transmission  of  tungsten  light  through  the  silver 

*  For  formula,  see  appended  table  of  formulas. 


July,  1943] 


REMOVAL  OF  HYPO  AND  SILVER  SALTS 


15 


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16  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 

sulfide  spot  when  the  transmitted  light  was  picked  up  by  a  photo- 
electric cell,  the  output  current  of  which  was  amplified  and  indicated 
on  a  microammeter. 

The  pH  of  solutions  was  determined  with  the  Beckman  Industrial 
pH  meter  standardizing  with  an  acid  phthalate  buffer  solution  at 
£H  =  3.97. 

The  relative  quantities  of  silver  in  prints  were  determined  by  spot 
testing  the  emulsion  side  with  0.2  per  cent  sodium  sulfide  solution 
and  visually  judging  the  intensities  of  the  silver  sulfide  stains. 

A  further  check  was  made  on  the  relative  silver  contents  by 
subjecting  samples  of  the  prints  to  accelerated  fading  conditions 
(over  water  at  110°F)  which  caused  the  silver  thiosulfate  complexes 
to  decompose  to  produce  a  silver  sulfide  stain. 

The  concentration  of  silver  in  fixing  baths  was  determined  by 
using  the  Argentometer  described  by  Weyerts  and  Hickman.9 

The  relative  rates  of  hypo  and  silver  removal  were  determined 
for  chrome  alum  (Kodak  F-23),  potassium  alum  (Kodak  F-25  or 
Kodak  F-5),  and  non-hardening  (Kodak  F-24)  fixing  baths,  and  the 
effect  of  increasing  £H  in  each  case  was  studied.  Two-bath  combin- 
ations of  these  three  types  and  modifications  of  them  were  also 
investigated. 

The  effect  of  a  series  of  wetting  agents  upon  the  removal  of  both 
hypo  and  silver  was  also  studied.  The  tests  indicated  that  the 
use  of  wetting  agents  had  no  practical  value  in  this  connection. 

EFFECT  OF  COMPOSITION  OF  PROCESSING  BATH 

(1)  Composition  of  the  Developer.— Tests  made  under  the 
same  conditions  of  rinsing,  fixing,  and  washing  with  Kodak  D-76,  DK- 
60a,  D-72  (1:2),  and  D-7  (pyro)  developers  showed  that  there  were 
no  differences  in  the  rate  of  removal  of  hypo  or  silver  from  Super- 
XX   Panchromatic    Negative   Film,  Type   1232,  when   using   the 
Kodak  F-5  fixing  bath. 

(2)  Composition  of  Stop  Baths. — Although  acid  stop  baths  are 
not  invariably  used  when  processing  negative  or  positive  films,  a 
comparison  between  water,  a  2  per  cent  solution  of  acetic  acid,  and 
a  3  per  cent  solution  of  chrome  alum  (Kodak  SB -3)  showed  that 
none  of  these  baths  had  any  appreciable  effect  in  retarding  or  hasten- 
ing washing  when  the  Kodak  F-5  fixing  bath  was  employed. 

(3)  Composition  of  Fixing  Baths. — Experiments  by  the  authors 
with  paper  prints  and  roll  films  have  shown  that  the  use  of  a  fresh 


July,  1943] 


REMOVAL  OF  HYPO  AND  SILVER  SALTS 


17 


chrome  alum  fixing  bath10  causes  an  increase  in  the  rate  of  hypo 
removal  as  compared  with  the  use  of  a  fresh  potassium  alum  fixing 
bath.  This  was  clearly  demonstrated  when  Plus-X  Panchromatic 
Negative  Film,  Type  1231,  was  washed  for  10  minutes  in  a  vertical 
glass  tube  with  different  quantities  of  water  flowing  through  the 
tube  per  unit  of  time.  The  quantity  of  residual  hypo  was  plotted 
against  the  rate  of  flow  as  shown  in  Fig.  2,  from  which  it  is  apparent 
that  the  rate  of  removal  from  chrome  alum  hardened  film  far  exceeds 
that  from  potassium  alum  hardened  film. 

With  a  chrome  alum  fixing  bath  apparently  the  hypo  is  not  so 
strongly  held  as  in  the  case  of  potassium  alum  baths  and  is  very 


30  60     100 


180    225 


GALLONS    PER    HOUR 


FIG.  2.  Effect  of  rate  of  flow  on  rate  of  removal  of  hypo  from 
A :  film  fixed  in  fresh  potassium  alum  fixing  bath  (Kodak  F-25)  \ 
B:  fresh  chrome  alum  fixing  bath  (Kodak  F-23).  Eastman 
Plus-Jf  Panchromatic  Negative  Film,  Type  1231.  Time  of  wash- 
ing, 10  minutes. 

readily  washed  from  the  film.  The  relatively  thick  Eastman  Motion 
Picture  Films,  Types  1231  and  1232,  when  washed  under  the  ex- 
treme conditions  of  5  minutes  in  the  experimental  apparatus  (Fig.  1) 
at  41  °F,  following  the  chrome  alum  fixing  bath,  retained  only  very 
small  quantities  of  hypo. 

The  use  of  a  non-hardening  fixing  bath  (Kodak  F-24)  without 
pre-  or  supplementary  hardening  was  slightly  more  effective  than 
the  use  of  a  chrome  alum  fixing  bath  with  respect  to  hypo  removal 
but  was  impractical  because  of  swelling  of  the  emulsion  and  the 
tendency  for  reticulation.  A  non-hardening  fixing  bath  is  practical 
only  when  used  in  combination  with  a  suitable  hardening  bath  or 
with  films  which  are  sufficiently  hardened  in  manufacture 

The  variations  in  concentration  of  hypo  in  the  fixing  baths  studied 
had  no  effect  on  the  rate  of  removal  of  hypo  from  processed  film. 


18  CRABTREE,  EATON,  AND  MUEHLER         [J.  s.  M.  p.  E. 

Other  ingredients  (exclusive  of  alums)  had  no  effect  provided  they 
did  not  change  the  pH  of  the  bath. 

Under  the  experimental  conditions  described  on  p.  13,  the  silver 
content  of  the  washed  film  was  essentially  zero. 

(4)  pH  of  Fixing  Baths.— The  pH  value  of  a  fixing  bath  is  signifi- 
cantly related  to  its  composition  which  results  from  a  consideration 
of  sulfurization  life,  hardening  properties,  rate  of  fixation,  exhaustion 
life,    and    sludging   properties.10-11      Various    fixing    bath    formulas 
therefore  give  different  initial  pH  values  as,  for  example, 

Kodak  F-23 — pH.  =  3 . 1 — Chrome  Alum 
Kodak  F-5  — pH  =  4 . 1 — Potassium  Alum-Boric  Acid 
Kodak  F-10 — pU.  =  4 . 6 — Potassium  Alum-Boric  Acid 
Kodak  F-6  — pU  =  4 . 9 — Potassium  Alum-Boric  Acid 

These  baths  were  compared  to  determine  whether  or  not  a  differ- 
ence in  initial  pH  affects  the  rate  of  elimination  of  hypo  from  film. 
It  is  considered  that  the  slight  differences  in  the  chemical  constituents 
of  the  potassium  alum  baths  were  unimportant  as  compared  with 
the  £H  differences. 

TABLE  II 

Effect  ofpH  of  Fixing  Baths  on  Rate  of  Removal  of  Hypo  (Eastman  Super -XX 1232} 

Time  of  Hypo  Content  (Mg  per  Sq-In) 

Washing  F-5  F-10  F-6  F-23 

(Min)  pH  =  4.1  pH  =  4.6  pH  =  4.9  pH  •»  3.1 

10  0.20  0.12  0.02  0.02 

25  0.08  0.06  Nil  Nil 

The  data  show  that  with  potassium  alum  baths  the  rate  of  removal 
of  hypo  is  greatest  with  baths  having  a  high  pH  value.  It  was  also 
found  that  by  adjusting  the  initial  pH  of  a  fixing  bath  to  a  higher  or 
lower  value  by  the  addition  of  alkali  or  acid,  a  corresponding  change 
in  the  rate  of  removal  of  hypo  resulted,  but  this  procedure  may 
impair  the  optimum  properties  of  the  fixing  bath.  Although  chrome 
alum  baths  have  low  initial  pH  values  there  is  no  appreciable  re- 
tention of  hypo  after  washing. 

(5)  Degree  of  Exhaustion  of  Fixing  Bath:    (a)  Effect  of  pH 
Change  on  Hypo  Removal. — The  F-23  chrome  alum,  F-5,  F-6,  and 
F-10  potassium  alum  fixing  baths  were  exhausted  to  approximately 
500  feet  per  gallon  with  Eastman  Super-JY^  Panchromatic  Nega- 
tive Film,  Type  1232,  and  the  pH,  degree  of  hardening,  and  rate 
of  removal  of  hypo  determined  at  different  stages  of  the  exhaustion. 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  19 

The  film  was  developed  in  D-76,  rinsed  5  seconds  in  running  water, 
fixed  for  20  minutes,  and  washed  for  10  and  25  minutes  in  the  ex- 
perimental washing  device  shown  in  Fig.  1.  In  order  to  maintain 
constant  the  quantity  of  fixing  bath  lost  by  carry-over  when  the 
film  samples  were  transferred  to  the  washing  apparatus,  the  films 
were  first  suspended  until  the  residual  fixing  bath  began  to  drain 
drop  wise. 

It  was  found  that  the  slight  increase  in  pH  (approximately  0.5 
unit)  of  the  F-5  fixing  bath  during  exhaustion  under  these  conditions 
was  not  sufficient  to  effect  any  appreciable  change  in  the  rate  of 
removal  of  hypo.  However,  when  the  ^>H  of  F-6  or  F-10  was  in- 
creased by  0.5  unit,  the  hypo  contents  of  the  films  decreased  as 
shown  below: 

Time  of 

Washing  F-10  F-10  F-6  F-6 

(Min)  0H-4.6  0H-5.1  0H-4.9     .  PH.-5A 

10  0.12  0.02  0.02  Nil 

25  0.06  Nil  Nil  Nil 

The  £H  of  the  F-23  chrome  alum  bath  increased  by  3  units.  Removal 
was  very  rapid  after  fixation  in  chrome  alum  baths  at  the  £H  of 
the  fresh  solution  and  more  rapid  at  higher  pH  values.  It  should 
be  remembered  that  with  chrome  alum  baths  the  initial  hardening 
and  non-sludging  properties  are  retained  for  not  more  than  24 
hours.10 

If  no  rinse  was  used  between  development  and  fixation  with 
F-5,  the  pH  increased  more  rapidly  and  effected  somewhat  greater 

TABLE  in 

Effect  of  Exhaustion  of  Fixing  Baths  on  Rate  of  Removal  of  Hypo 

Comparison   of  "Rinse"   and   "No   Rinse"   Between  Development  and   Fixation 

Eastman  Super -XX  Panchromatic  Negative  Film,  Type  1232 

Hypo  Content 
(Mg  per  Sq-In) 
Wash,  Wash, 

Bath  pH  10  Min  20  Min 

F-5,  fresh  unused  4.1  0 . 18  >0 . 04 

F-5,  exhausted  to  400  ft  per  gallon  with 

rinse  4.60  0.14  0.34 

F-5,  exhausted  to  400  ft  per  gallon,  no  rinse  5.45          <0.005          <0.005 
F-5,  exhausted  to  400  ft  per  gallon  with 

rinse,  pH  adjusted  4.1  0.18  0.04 

F-5,  exhausted  to  400  ft  per  gallon,  no 

rinse,  pH  adjusted  4.1  0.18  0 . 04 


20 


CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 


changes  in  the  rate  of  removal  of  hypo  as  shown  in  Table  III.  These 
pH  effects  were  further  verified  when  the  pH  of  the  exhausted  baths 
was  adjusted  to  the  />H  value  of  the  fresh  bath. 

(b)  Effect  of  Silver  Content  on  Removal  of  Silver  and  Hypo. — As 
mentioned  previously,  the  concentration  of  silver  in  the  clear  portions 
of  the  film  is  almost  as  important  with  respect  to  permanence  as 
the  residual  hypo  in  the  film.  As  is  the  case  with  hypo,  if  the  storage 


0.14 


FRESH 


AGO 


EXHAUSTION  (FEET  35  mm.  FILM  PER  GAL.) 


FIG.  3.  Effect  of  exhaustion  of  fixing  bath  on  hypo 
and  silver  content  after  washing.  Eastman  Super-XX 
Panchromatic  Negative  Film,  Type  1232.  Fixed  in 
Kodak  F-5.  Washed  5  minutes  at  68°F. 

pH  of  fixing  bath  maintained  at  4.1. 

pH.  of  fixing  bath  increased  with  exhaustion  to 

5.5. 

conditions  with  film  or  prints  are  favorable,  the  silver  thiosulfate 
complexes  are  not  particularly  harmful  in  the  absence  of  hydrogen 
sulfide  in  the  air.  However,  if  any  unfavorable  change  occurs  in 
these  conditions,  the  complexes  decompose  to  produce  a  yellow 
stain  of  silver  sulfide  which  is  proportional  in  intensity  to  the  quantity 
of  silver  retained.  A  study  was  therefore  made  of  the  effect  of  the 
degree  of  exhaustion,  the  pH  during  exhaustion,  and  the  degree 
of  washing  on  the  relative  quantities  of  silver  and  hypo  retained  by 
the  film. 

Unexposed    Eastman   Motion   Picture   Super-XJ^    Panchromatic 


July,  1943] 


REMOVAL  OF  HYPO  AND  SILVER  SALTS 


21 


Negative  Film,  Type  1232,  was  developed  as  recommended  and  then 
fixed  for  four  times  the  apparent  "time  to  clear"  (see  "Time  of  Fixa- 
tion," p.  25)  in  the  Kodak  F-5  potassium  alum  fixing  bath  without 
the  use  of  a  rinse  between  development  and  fixation.  The  fixing 
baths  used  were  both  fresh  and  exhausted  to  100,  200,  300,  and  400 
feet  per  gallon.  Similar  tests  were  made  with  Eastman  Motion 
Picture  Positive  Film,  Type  1301,  and  all  tests  with  both  emulsions 
duplicated  in  the  Kodak  F-23  chrome  alum  fixing  bath  and  in  the 
Kodak  F-24  bisulfite-sulfite  non-hardening  fixing  bath. 


5         10  2.0  50 

WASHING  (MINUTES)   68°F 


I       5        10  20  5O 

WASHING  (MINUTES)  <be°p 


FIG.  4.  Effect  of  exhaustion  of  fixing  bath  on  rate  of  removal  of  hypo  by 
washing.  Eastman  Super- JO"  Panchromatic  Negative  Film,  Type  1232. 
Fixed  in  Kodak  F-5. 

Curve  A—  Fresh  bath,  pR  =  4.1. 

B — Exhausted  to  100  feet  per  gallon,  pR  =  4.3. 
C—  Exhausted  to  200  feet  per  gallon,  pR  =  4.7. 
D — Exhausted  to  300  feet  per  gallon,  pR  =  5.1. 
E — Exhausted  to  400  feet  per  gallon,  pR  =  5.5. 

(a)  pR  maintained  at  4.1. 

(b)  pR  increased  with  exhaustion  from  4.1  to  5.5  as  shown  above. 


The  curves  in  Figs.  3,  4,  and  5  illustrate  the  effects  of  the  degree 
of  exhaustion  and  changes  of  pH.  of  the  F-5  fixing  bath  on  the  rates 
of  removal  by  washing  of  hypo  and  silver  from  processed  Motion 
Picture  Negative  Film,  Type  1232. 

Fig.  3  illustrates  two  important  relationships  between  the  hypo 
and  silver  contents  of  the  film  after  a  given  washing  time  of  5  minutes, 
namely: 

(1)  If  the  pH  of  the  fixing  bath  was  maintained  during  exhaustion 
at  the  pH  of  the  fresh  bath,  the  residual  hypo  content  was  essentially 
constant  while  the  silver  content  increased  appreciably. 

(2)  If  the  £H  of  the  fixing  bath  was  allowed  to  increase  (4.1  to 
5.5)   by  carry-over  of  developer   during  exhaustion,   the  residual 


22 


CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 


hypo  content  decreased  to  a  low  value  and  the  silver  was  completely 
removed  at  pH  values  greater  than  4.9,  which  is  the  isoelectric 
point  of  gelatin  (see  p.  43).  The  pH  of  the  bath  exhausted  to  300 
feet  per  gallon  was  5.1. 

Further  experiments  indicated  that  after  a  washing  time  of  30 
minutes  the  hypo  content  was  reduced  to  zero  when  the  pH.  of  the 
bath  increased  to  5.5,  but  when  the  pH  was  maintained  constant  at 
4.1,  the  hypo  content  decreased  to  a  certain  small  quantity  not  re- 


s     10  20  30 

WASHING  (MINUTES)  68° 


I        5         10  10 

WASHING  (MINUTES) 


3O 


FIG.  5.  Effect  of  exhaustion  of  fixing  bath  on  rate  of  removal  of  silver 
by  washing.  Eastman  Super- JO"  Panchromatic  Negative  Film,  Type  1232. 
Fixed  in  Kodak  F-5. 

Curve  A — Fresh  bath,  pR  =  4.1. 

B — Exhausted  to  100  feet  per  gallon,  pR  =  4.3. 
C—  Exhausted  to  200  feet  per  gallon,  pH.  =  4.7. 
D — Exhausted  to  300  feet  per  gallon,  pH.  =  5.1. 
E — Exhausted  to  400  feet  per  gallon,  pH.  =  5.5. 

(a)  pH  maintained  at  4.1. 

(b)  pH.  increased  with  exhaustion  from  4.1  to  5.5  as  shown  above. 


movable  by  further  washing.  Silver  was  retained  only  after  fixation 
in  the  baths  exhausted  to  about  200  feet  per  gallon  when  the  pYL 
was  maintained.  The  quantity  of  this  residual  silver  after  a  30- 
minute  wash  was  approximately  20  per  cent  lower  than  after  a 
5-minute  wash  and  remained  constant  even  after  two  hours'  washing. 
These  facts  are  substantiated  in  greater  detail  in  Fig.  4.  The 
curves  in  Fig.  4(a)  and  (b)  indicate  the  relative  rates  of  removal 
of  hypo  for  increasing  times  of  washing  after  fixation  in  baths  ex- 
hausted to  varying  degrees  (1)  with  the  pH  maintained,  and  (2) 
at  increasing  pYL  values  in  the  range  4.1  to  5.5.  An  increase  in  pH 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  23 

increased  appreciably  the  rate  of  removal  of  the  hypo  but,  after 
fixation  in  the  baths  exhausted  to  about  200  feet  of  35-mm  film  per 
gallon  and  with  the  pH  maintained,  the  hypo  content  could  not 
be  reduced  entirely  to  zero  by  any  amount  of  washing. 

The  curves  in  Fig.  5  (a)  and  (b)  show  a  similar  effect  of  pH  on  the 
rate  of  removal  of  silver,  namely,  that  above  a  degree  of  exhaustion 
of  approximately  200  feet  per  gallon  the  silver  can  not  be  removed 
entirely  by  washing  when  the  £H  is  maintained. 

It  is  therefore  apparent  that  after  a  certain  degree  of  exhaustion, 
if  the  pH  of  the  fixing  bath  is  maintained  constant,  neither  the  hypo 
nor  the  silver  is  completely  removable  by  washing.  A  study  of 
the  relative  quantities  of  hypo  and  silver  retained  after  fixation 
in  baths  exhausted  to  different  degrees  in  the  range  from  250  to 
500  feet  per  gallon  showed  that  the  retention  of  silver  approximately 
paralleled  that  of  the  hypo. 

The  curves  in  Figs.  4  and  5  show  that  an  increase  in  the  £>H  of 
the  fixing  bath  to  a  value  above  4.9  permitted  the  complete  removal 
of  the  hypo  and  silver.  Complete  removal  may  also  be  accomplished 
by  bathing  the  film  in  an  0.03  per  cent  ammonia  solution  (1  cc  of 
28  per  cent  ammonia  per  liter)  following  washing  of  the  film  or  by 
the  use  of  a  fresh  second  fixing  bath  as  described  later. 

In  general,  similar  results  were  obtained  when  a  chrome  alum 
fixing  bath  (Kodak  F-23)  was  used.  The  hypo  content  decreased 
with  time  of  washing  much  more  rapidly  than  as  indicated  in  Fig.  4, 
except  for  a  small  quantity  retained  by  the  film  following  fixation 
in  exhausted  baths,  when  the  residual  silver  and  hypo  contents  were 
somewhat  less  than  those  retained  after  fixation  with  exhausted 
potassium  alum  baths.  However,  prolonged  washing  removed  some 
of  the  residual  silver  and  hypo  retained  after  chrome  alum  fixation 
but  had  little  effect  on  that  retained  after  potassium  alum  fixation 
when  the  pH  of  the  bath  was  maintained. 

With  the  bisulfite-sulfite  non-hardening  fixing  bath,  there  was 
no  retention  of  hypo  or  silver  following  any  degree  of  exhaustion, 
and  the  hypo  was  removed  somewhat  more  rapidly  than  after  fixing 
with  chrome  alum  baths. 

Data  from  experiments  with  finer-grained  and  more  thinly  coated 
films,  such  as  Eastman  Motion  Picture  Release  Positive  Film, 
Type  1301,  and  Fine-Grain  Release  Positive  Film,  Type  1302, 
indicated  that  the  same  general  effects  were  obtained  but  to  a  lesser 
degree  than  with  the  high-speed  negative  film,  Type  1232.  A  factor 


24 


CRABTREE,  EATON,  AND  MUEHLER         [j.  s.  M.  P.  E. 


of  four  times  the  apparent  "time  to  clear"  was  also  used  for  the 
time  of  fixation  with  these  films. 

(c)  Effect  of  Original  pH  of  Fixing  Baths  on  Removal  of  Silver 
from  Film. — Figs.  4  and  5  show  that  complete  removal  of  silver 
and  hypo  was  possible  when  the  pH  of  the  F-5  fixing  bath  was 
allowed  to  increase  during  exhaustion  to  values  above  4.9.  When 
the  pH  was  maintained,  the  silver  content  of  the  film  increased  with 
exhaustion.  Tests  were  made  to  determine  the  effect  of  the  pH  of 
different  fixing  baths,  when  maintained  during  exhaustion,  on  the 
silver  retained. 

The  fixing  baths  used  were  F-5  at  pH  =  4.1,  F-10  at  pH  =  4.6, 


QO4 


003 


001 


125  250  375  5OO 

DEGREE  OF  EXHAUSTION  :  FEET  35mm.  FILM  PER  GALLON 

FIG.  6.  Effect  of  fixing  bath  pR  on  retention  of  silver  by  films 
when  original  />H  value  is  maintained  during  exhaustion.  East- 
man Super-ZZ  Panchromatic  Negative  Film,  Type  1232.  Washed 
20  minutes. 


F-6  at  £H  =  4.9,  and  F-23  at  £H  =  3.1  and  these  were  exhausted  to 
125,  250,  375,  and  500  feet  of  35-mm  Super-^X  Panchromatic 
Negative  Film,  Type  1232,  per  gallon.  The  film  strips  washed  for 
20  minutes  in  the  apparatus  described  in  Fig.  1  were  spot-tested 
with  sodium  sulfide  and  the  transmission  densities  of  the  silver  sulfide 
spots  determined.  The  relative  silver  contents  expressed  in  these 
density  units  were  plotted  against  the  degrees  of  exhaustion  as  shown 
in  Fig.  6. 

The  curves  show  that  less  silver  was  retained  as  the  pH  of  the 
bath  increased  from  4.1  to  4.9  and  that  somewhat  less  silver  was 
retained  by  film  fixed  in  an  exhausted  chrome  alum  bath. 

(6)  Replacement  of  Sodium  Thiosulfate  with  Ammonium 
77ii'osu//0te.— Equimolecular  (14.4%)  and  semimolecular  (7.2%) 
concentrations  of  ammonium  thiosulfate  were  substituted  for  the 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  25 

sodium  thiosulfate  in  the  Kodak  F-5,  F-23,  and  F-24  solutions  and 
these  baths  compared  with  the  regular  formulas.  The  addition  of  am- 
monium thiosulfate  to  the  baths  increased  the  pH  somewhat  so  that 
an  adjustment  to  the  pH  of  the  regular  baths  was  necessary. 

With  substitution  in  the  F-5  bath,  washing  tests  indicated  that 
after  fixing  in  the  7.?  per  cent  ammonium  thiosulfate  bath  the 
rate  of  removal  of  hypo  was  equal  to  that  with  the  regular  bath 
but,  after  fixing  in  the  14.4  per  cent  bath,  the  rate  was  approximately 
30  per  cent  greater.  No  differences  were  measurable  between 
sodium  and  ammonium  thiosulfate  in  the  case  of  the  chrome  alum 
(F-23)  or  non-hardening  (F-24)  fixing  baths.  With  respect  to 
silver,  any  differences  were  so  small  that  they  were  not  detectable 
by  the  sulfide  test. 

EFFECT  OF  VARIOUS  FACTORS 

(/)  Time  of  Fixation. — Tests  were  made  with  developed  Eastman 
Motion  Picture  Super- JO"  Panchromatic  Negative  Film,  Type  1232, 
and  Eastman  Motion  Picture  Release  Positive  Film,  Type  1301, 
in  both  fresh  and  exhausted  sulfite- bisulfite  (F-24),  potassium  alum- 
boric  acid  (F-5)  and  chrome  alum  (F-23)  fixing  baths.  The  baths 
were  exhausted  to  125,  250,  375,  and  500  feet  per  gallon  with  (a) 
the  £H  maintained  at  the  pH  of  the  fresh  bath,  and  (b)  the  £H 
increased  by  carry-over  of  developer.  The  times  of  fixing  used 
were  2,  4,  6,  and  10  times  the  apparent  "time  to  clear"  in  each  bath. 
All  test  strips  were  washed  for  15  minutes. 

The  "time  to  clear"  of  an  emulsion  is  a  somewhat  variable  factor 
and  dependent  upon  (a)  the  nature  and  intensity  of  the  incident 
light  used  to  observe  the  clearing  point  (by  refraction),  and  (b)  the 
ability  of  the  individual  to  judge  the  clearing  point.  It  is  particularly 
difficult  to  determine  in  the  case  of  exhausted  fixing  baths  because 
of  the  very  low  rate  of  conversion  of  the  halides  to  soluble  com- 
plexes. For  these  reasons  the  term  "apparent  time  to  clear"  was 
preferred. 

The  most  satisfactory  method  of  viewing  was  to  direct  a  beam  of 
tungsten  light  between  the  film  and  a  black  background  at  an  angle 
of  approximately  45  degrees  to  the  background.  The  most  accurate 
"time  to  clear"  determination  required  uniform  agitation  such  that 
the  conversion  of  the  halides  was  uniform  over  the  entire  emulsion 
area.  Relative  clearing  and  fixing  times  should  be  determined  at  a 
fixed  temperature,  for  example,  68°F. 


26 


CRABTREE,  EATON,  AND  MUELHER         [j.  s.  M.  P.  E. 


Under  average  darkroom  conditions  the  results  were  usually 
within  5  per  cent  when  uniform  agitation  was  employed  and,  al- 
though tungsten  light  provided  the  best  lighting  conditions,  the 
light  from  a  Series  OA,  1,  or  3  safelight,  although  less  intense,  did 
not  alter  the  "apparent  time  to  clear"  when  transmitted  rather 
than  reflected. 

Since  the  removal  of  the  last  traces  of  residual  silver  is  necessary 
for  archival  purposes,  tests  were  made  with  the  F-5  fixing  bath  and 
the  negative  film,  Type  1232,  to  determine  the  best  time  of  fixing 


'  (I)    F-5  EXHAUSTED  375  FT.  PER  GAL  pH  MAINTAINED  AT4 

(2)  F-5  EXHAUSTED  375  FT  PER  GAL    pH   AT  5.2S 

(3)  F-5   FRESH    pH4.l 

(4)  F-5  FRESH    pH  525 


MULTIPLES   OF  "TIME  TO  .CLEAR11  IN  F-5   FIXING   BATH 

FIG.  7.  Effect  of  increasing  time  of  fixation  on  the 
residual  silver  content  of  film  with  fixing  bath  pH  main- 
tained at  4.1;  with  fixing  bath  pH.  at  5.25.  Kodak 
Fixing  Bath  F-5.  Eastman  Super-JO"  Panchromatic 
Negative  Film,  Type  1232. 


to  accomplish  this.  The  fresh  fixing  bath  at  pH  =  4.1  was  compared 
with  the  fresh  bath  adjusted  to  pH  —  5.25,  with  exhausted  .F-5 
at  pH  =  5.25,  and  with  exhausted  F-5  adjusted  to  pU  =  4.1.  The 
curves  in  Fig.  7  show  that  (a)  either  a  fresh  or  exhausted  bath  at  a 
pH  above  4.9  permits  the  removal  of  the  last  traces  of  silver  from 
the  negative  film  after  fixing  for  twice  the  apparent  "time  to  clear" 
and  (b)  a  fresh  bath  at  its  original  pH  (4.1)  required  four  times  the 
apparent  time  to  clear  in  order  to  make  complete  removal  of  the 
last  traces  of  silver  possible,  but  an  exhausted  bath  when  adjusted 
to  pH  4.1  or  to  any  value  below  4.9  caused  the  retention  of  a  con- 
siderable quantity  of  silver.  Similar  results  were  obtained  with  the 


July,  1943] 


REMOVAL  OF  HYPO  AND  SILVER  SALTS 


27 


positive  film,  Type  1301,  except  that  the  quantities  of  silver  retained 
were  somewhat  less. 

The  actual  difference  in  the  quantities  of  silver  retained  after 
fixing  for  twice  and  four  times  the  "time  to  clear"  in  the  F-5  fixing 
bath  at  £H  =  4.1  is  admittedly  small  and  may  be  of  no  practical 
significance.  However,  since  removal  by  washing  of  the  last  traces 
of  silver  was  desired,  a  fixing  time  of  four  times  the  apparent  time 
to  clear  was  used  in  both  fresh  and  exhausted  baths  throughout 
this  investigation. 

When  the  times  of  fixing  were  extended  to  six  and  ten  times 
the  apparent  "time  to  clear,"  the  Super-^JY  Negative  film,  Type 


0.09 
0.08 
GOT 


0.05 


002 
001 


EXHAUSTION   pH  VALUES 

FRESH     4-.  I 
1 25  FT /GAL.  4.5O 
25OFT/GAL.  4.9O 
375  FT/ GAL.   5.25  'Ox; 

500  FT/ GAL.  S.fcO 


'EXHAUSTION 
pHs. 


125  25O  375  BOO 

DEGREE  OF  EXHAUSTION:  FEET  35mm   FILM  PER  GALLON 

FIG.  8.  Silver  retained  after  increasing  times  of  fixation  in 
exhausted  baths.  Kodak  Fixing  Bath  F-5.  Film  washed  15 
minutes.  Eastman  Super-JOf  Panchromatic  Negative  Film, 
Type  1232. 

1232,  retained  an  almost  constant  quantity  of  silver  after  fixing  in 
an  exhausted  bath  with  the  £H  maintained  at  4.1,  as  shown  in  Fig.  7, 
but  retained  no  silver  when  the  £H  was  greater  than  4.9. 

It  was  of  interest  to  determine  the  extent  of  the  retention  of  silver 
at  various  stages  of  the  exhaustion  life  of  a  fixing  bath  when  the 
£>H  was  maintained  at  4.1  and  when  it  was  allowed  to  increase  by 
addition  of  "carry-over"  developer.  The  data  and  curves  for  tests 
made  with  Eastman  Super-JO  Negative  Film,  Type  1232,  are  given 
in  Fig.  8  in  which  the  relative  silver  contents  are  plotted  in  density 
units  obtained  by  reading  silver  sulfide  spots  as  previously  described. 
Three  facts  are  evident,  namely,  (a)  when  the  pH  was  below  4.5, 
the  silver  retained  increased  with  exhaustion,  (b)  when  the  p*K  of  the 
baths  reached  4.9,  the  silver  content  was  almost  zero  and  at  pH 


28 


CRABTREE,  EATON,  AND  MUEHLER         [j.  s.  M.  P.  E. 


=  5.25  no  silver  was  retained,  which  verifies  the  data  illustrated 
in  Figs.  4  and  5,  and  (c)  there  was  very  little  variation  in  the 
quantity  of  silver  retained  after  fixing  for  times  longer  than  four 
times  the  time  to  clear. 

The  curves  in  Fig.  9  illustrate  the  results  of  similar  experiments 
made  with  Eastman  Motion  Picture  Release  Positive  Film,  Type 
1301.  Three  facts  are  evident  from  these  curves,  namely,  (/)  when 
the  pH  during  exhaustion  was  allowed  to  increase  to  4.9  only  a 
very  minute  trace  of  silver  remained  in  the  sample  fixed  for  ten 
times  the  apparent  "time  to  clear,"  (2)  when  the  pH  was  main- 


D  0.10 

£  0.09 

5  008 

^  O.OT 

|  0.06 

8  0.05 

u  0.04- 

5  001 

£  ooz 

w  ooi 


FRESH 


125  250  375  50O 

DEGREE     OF  EXHAUSTION.  FEET    55nrm.  PER.  GM.LOK1 


FIG.  9.  Silver  retained  after  increasing  times  of  fixation  in 
exhausted  baths.  Kodak  Fixing  Bath  F-5.  Film  washed  15 
minutes.  Eastman  Positive  Film,  Type  1301. 


tained  below  4.9  the  silver  content  increased  with  exhaustion  but  the 
absolute  quantities  were  less  than  those  retained  by  Super- JOT 
Negative  Film,  Type  1232  under  the  same  conditions,  and  (3)  with 
the  pYL  maintained  below  4.9  the  quantity  of  silver  retained  in- 
creased somewhat  with  the  longer  times  of  fixation  for  a  given  degree 
of  exhaustion. 

With  the  Release  Positive  Film,  Type  1301,  the  quantity  of  residual 
silver  increased  somewhat  after  extended  times  of  fixing  (for  example, 
from  2  to  10  times  the  apparent  time  to  clear)  but  no  such  increase 
occurred  with  the  Super-^Y^  Negative  Film,  for  similar  multiples 
of  the  apparent  time  to  clear.  The  actual  time  in  minutes  in  the 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  29 

fixing  bath  and  the  relationship  of  this  time  to  the  degree  of  hardening 
of  the  film  should  explain  this  anomaly. 

The  apparent  time  to  clear  in  fresh  F-5  was  approximately  30 
seconds  for  the  Release  Positive  Film,  and  3  minutes  15  seconds  for 
the  Super-XX"  Negative  Film.  Therefore,  four  and  ten  times  the 
time  to  clear  the  films,  Release  Positive  and  Super-^O  Negative, 
in  fresh  and  exhausted  -F-5  baths  were : 

Release  Positive  Super-XX  Negative 

Type  1301  Type  1232 

Fresh  bath  4X  2  Min  13  Min 

10  X  5  Min  32V2  Min 

Exhausted  bath  4X  4  Min  26  Min 

10  X  10  Min  65  Min 

The  degree  of  hardening  produced  in  an  F-5  fixing  bath  increased 
from  about  150°F  to  near  the  maximum  in  1  to  10  minutes  and 
reached  the  maximum  in  about  20  minutes  (Fig.  10).  It  is  believed 
that  the  gelatin-hardener  complex  is  responsible  for  the  retention 
of  the  silver  and  that  as  the  degree  of  hardening  increases  the  retention 
of  silver  increases  provided  the  £H  of  the  bath  is  below  4.9.  This 
would  suggest  that  the  quantity  of  residual  silver  does  not  increase 
with  Super- XX  Negative  Film,  because  the  maximum  degree  of 
hardening  is  obtained  in  four  times  the  apparent  time  to  clear  in  a 
fresh  bath.  However,  it  can  increase  with  Release  Positive  Film 
because  the  degree  of  hardening  increased  rapidly  during  the  periods 
of  "four"  and  "ten"  times  the  "time  to  clear." 

Thus,  from  the  standpoint  of  residual  silver,  extended  times  of 
fixation  in  potassium  alum  baths  at  ^>H's  below  4.9  have  no  ad- 
vantage especially  in  exhausted  or  partially  exhausted  baths.  To 
remove  the  silver  completely,  the  use  of  multiple  fixing  baths  must 
be  considered. 

When  a  fresh  chrome  alum  (F-23)  or  fresh  bisulfite-sulfite  (F-24) 
fixing  bath  was  used,  the  rate  of  removal  of  hypo  was  so  great  as 
compared  with  the  rate  when  a  potassium  alum  fixing  bath  (F-5) 
was  used  that  all  of  the  hypo  was  removed  in  approximately  10 
minutes  following  any  time  of  fixation  up  to  30  minutes. 

After  fixation  in  exhausted  chrome  alum  baths  for  the  recom- 
mended times,  both  silver  and  hypo  as  a  complex  were  retained  by 
the  film  in  approximately  the  same  ratio  and  quantity  as  following 
fixation  in  a  potassium  alum  bath.  However,  with  prolonged 


30 


CRABTREE,  EATON,  AND  MUEHLER         [j.  s.  M.  P.  E. 


fixation  in  exhausted  chrome  alum  baths  there  was  no  increase  in 
the  quantity  of  retained  silver  thiosulfate  complex. 

(2)  Use  of  Two  Fixing  Baths.— Several  combinations  of  fixing 
baths  were  studied  to  determine  the  effect  on  the  rate  of  removal  of 
hypo,  the  degree  of  hardening,  and  the  rate  of  elimination  of  the 
silver  from  the  processed  film.  A  potassium  alum  hardening  fixing 
bath  (Kodak  F-5)  was  used  as  the  first  bath  and  either  (a)  a  non- 
hardening  bath  F-24  (/>H  =  5.6),  (b)  a  non-hardening  bath,  F-5 
without  alum  (pH  =  4.5),  or  (c)  a  chrome  alum  bath  F-23  used  as 
the  second  bath. 


s        7  10 

TIME  OF  FIXATION   (MINUTES) 


15 


FIG.  10.  Effect  of  time  of  fixation  on  degree  of  hardening. 
Eastman  Motion  Picture  Positive  Film.  Type  1301.  Kodak  F-5 
Fixing  Bath  (fresh  pU;  4.1). 

When  emulsion  1232  was  fixed  in  each  of  these  fixing  bath  com- 
binations, the  residual  hypo  content  in  the  film  varied  considerably 
for  a  given  washing  time  as  shown  in  Table  IV.  A  time  of  20  minutes 
in  the  first  bath  (to  insure  a  maximum  degree  of  fixation  in  the 
exhausted  baths)  and  5  minutes  in  the  second  bath  was  employed. 

TABLE  IV 


Effect  of  Second  Fixing  Bath  on  Rate  of  Removal  of  Hypo 

Time  of 
Washing 
(Min)          F-5  F-5:  F-5 


Hypo  Content  (Mg  per  Sq-In) 
F-5: F-5 
(No  Alum)  F-5:  F-24  F-5:  F-23 


10 
25 


0.20 
0.05 


0.20 
0.04 


0.02 
Nil 


0.005 
Nil 


0.06 
Nil 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  31 

The  F-5  (no  alum),  F-24,  and  F-23  combinations  with  F-5  in- 
creased the  rate  of  removal  of  hypo  greatly  but  the  two  baths  of 
F-5  were  no  different  from  F-5  alone.  The  degree  of  hardening  was 
equal  in  the  F-5  and  the  F-5:F-5  combination  but  increased  some- 
what with  exhaustion  when  using  the  F-5  followed  by  the  F-23. 
The  hardening  was  decreased  slightly  when  using  F-5  followed  by 
F-24. 

When  exhaustion  studies  of  the  F-5: F-24  combination  were  made 
it  was  found  that  the  F-24  bath  began  to  sludge  after  the  bath  was 
only  half  exhausted.  This  difficulty  was  overcome  (a)  by  using 
an  intermediate  water  rinse,  (b)  by  using  the  F-5  fixing  bath  with 
the  alum  omitted  as  the  second  bath,  or  (c)  by  lowering  the  pH  value 
of  F-24  from  5.6  to  4.5  by  the  addition  of  acetic  acid.  When  (c) 
was  employed  the  rate  of  removal  of  hypo  was  the  same  as  with  the 
F-5: F-5  (no  alum)  combination.  In  this  manner  sludging  did  not 
occur  during  the  exhaustion  life  of  the  bath. 

The  use  of  F-6  as  a  second  bath  was  very  effective  for  hypo  re- 
moval, the  hypo  content  of  the  film  being  0.04  milligram  per  square- 
inch  after  10  minutes'  washing.  However,  with  this  combination 
(F-5: F-6)  it  was  necessary  to  maintain  the  £H  of  the  F-6  bath  at 
4.9  to  5.5  or  its  effectiveness  would  be  lost  because  of  a  lowering 
of  the  pH  by  the  carry-over  of  the  more  acid  F-5  fixing  bath. 

The  silver  content  of  the  film  was  essentially  reduced  to  zero 
throughout  the  exhaustion  when  a  second  fixing  bath  was  used  for 
2  to  5  minutes  after  the  first  F-5  fixing  bath,  regardless  of  the  com- 
position of  the  second  bath. 

It  has  been  shown  that  when  the  degree  of  exhaustion  of  a  single 
bath  (pH  maintained)  exceeded  200  feet  of  35-mm.  film  per  gallon, 
silver  was  permanently  retained  by  the  film  even  after  prolonged 
washing.  A  second  fixing  bath  should  therefore  be  used  and  may 
be  exhausted  to  the  point  where  silver  is  permanently  retained  by  the 
film. 

When  the  pH  of  the  first  bath  was  maintained  during  exhaustion 
the  pH  of  the  second  bath  did  not  change  appreciably,  but  if  the 
pH  of  the  second  bath  was  low  (e.  g.,  F-5  at  £H  =  4.1)  the  degree  of 
exhaustion  was  limited  by  the  silver  retained  by  the  film.  On  the 
other  hand,  if  the  pH  of  the  second  bath  was  above  £H  =  4.9,  the 
degree  of  exhaustion  was  limited  only  by  other  factors  such  as  sludg- 
ing properties. 

The  relationship  between  the  quantities  of  silver  in  the  fixing 


32 


CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 


bath  and  the  silver  retained  by  Eastman  Super-XJf  Negative  Film, 
Type  1232,  is  shown  in  Fig.  11  when  two  7^-5  fixing  baths  were  used 
with  the  pH  maintained  at  4.1.  It  is  apparent  that  the  silver 
content  increases  very  rapidly  in  the  first  bath  from  the  start  of  the 
exhaustion  and  increases  rapidly  in  the  second  bath  only  after  500 
feet  per  gallon  have  been  fixed.  The  silver  content  of  the  film  in- 
creased rapidly  after  fixation  in  the  first  bath,  but  following  the 
second  bath,  the  content  was  zero  until  250  feet  per  gallon  were 


125          25O         375          5OO        625        75O         875 
PEGREE  OF  EXHAUSTION     FEET  35mm. FILM  PER  GAL. 

FIG.  11.  Effect  of  exhaustion  on  concen- 
tration of  silver  in  first  and  second  fixing 
baths  and  in  film  fixed  in  these  baths. 
Eastman  Motion  Picture  Super-.X'.X"  Pan- 
chromatic Negative  Film,  Type  1232. 
Kodak  Fixing  Bath  F-5.  £H  maintained. 
Film  washed  15  minutes. 


fixed  when  it  began  to  increase.  The  exhaustion  life  of  this  com- 
bination of  baths  is  dependent  upon  the  proposed  use  of  the  proc- 
essed film. 

The  use  of  any  single  bath  or  combinations  of  baths  which  have 
pH  values  higher  than  pH  —  4.9  prevents  the  retention  of  silver. 

(3)  Effect  of  Separated  Hardening  and  Fixing. — A  study  was 
made  of  the  removal  of  hypo  and  silver  when  the  hardening  and 
fixing  operations  were  performed  in  separate  baths.  Negative 
film,  Type  1232,  was  hardened  in  a  potassium  alum  bath  which  was 
essentially  F-5  without  hypo  for  10  minutes  and  then  fixed  in  fresh 


July,  1943]          REMOVAL  OF  HYPO  AND  SILVER  SALTS  33 

F-5  without  alum  for  10  minutes.*  These  operations  were  then 
reversed  and  a  comparison  made  with  an  emulsion  processed  (/) 
in  F-5  and  (2)  with  a  chrome  alum  hardening  stop  bath  (SB-3)  in 
combination  with  a  bisulfite-sulfite  non-hardening  fixing  bath  (F-24). 

The  analyses  indicated  that  in  the  case  of  potassium  alum  harden- 
ing baths  hardening  should  take  place  before  fixation  to  obtain  the 
best  conditions  for  effective  hypo  removal.  The  most  effective 
combination  was  the  chrome  alum  hardening  bath  (SB-3)  followed 
by  the  bisulfite-sulfite  non-hardening  fixing  bath  but  this  combina- 
tion was  no  better  than  the  use  of  a  chrome  alum  fixing  bath  (F-23) 
alone.  However,  tests  with  shorter  times  of  washing  in  a  less 
effective  washing  system  than  that  illustrated  in  Fig.  1  showed  that 
the  SB-3:  bisulfite-sulfite  fixing  bath  combination  was  more  effective 
than  F-23  alone.  When  exhausted  fixing  baths  were  used,  the 
retention  of  silver  paralleled  that  of  the  hypo. 

(4)  Temperature  of  Processing. — The  results  of  several  experi- 
ments with  various  films  indicated  that  for  a  fixed  washing  tempera- 
ture large  temperature  differences  between  the  developer  or  fixing  bath 
and  the  wash  water  resulted  in  only  small  differences  in  the  rate 
of  elimination  of  hypo  and  no  differences  in  the  rate  of  elimination 
of  silver. 

WASHING 

(1)  Effect  of  Nature  of  Water:  (a)  pH  of  the  Wash  Water.— The 
pH  of  the  wash  water  has  a  very  definite  effect  upon  the  rate  of 
removal  of  hypo  as  shown  in  Table  V.  Eastman  Fine-Grain  Release 
Positive  Film,  Type  1302,  was  developed,  fixed,  and  washed  for  5 
minutes  at  65°F  in  tap  water  at  a  />H  of  approximately  7.0,  and  then 
further  washed  by  bathing  in  trays  of  water  at  different  pH  values. 

TABLE  v 

Effect  of  pH  of  Wash  Water  on  Rate  of  Removal  of  Hypo  (Potassium  Alum  Fixing 

Bath) 
Eastman  Fine  Grain  Release  Positive  Film,  Type  1302 

Concentration  of  Hypo  (Mg  per  Sq-In) 
£H  2  Min  Washing  5  Min  Washing 

3.4  0.13  0.07 

5.4  0.09  0.05 

8.0  0.04  0.02 

10.0  Nil  Nil 

*  Formulas  of  this  type  are  necessary  because  those  similar  to  the  non-harden- 
ing F-24  fixing  bath  sludge  when  only  one-half  exhausted. 


34  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 

It  is  seen  that  an  increase  in  pH  of  the  wash  water  caused  a  de- 
crease in  the  time  required  to  eliminate  a  given  quantity  of  hypo 
from  a  given  emulsion.  This  fact  is  of  practical  importance,  es- 
pecially where  an  alkaline  water  supply  is  used,  and  is  contrary 
to  the  claims  of  D.  K.  Allison12  that  washing  with  water  adjusted 
to  the  isoelectric  point  of  the  gelatin  will  produce  the  most  efficient 
hypo  removal,  but  it  substantiates  the  results  of  Sheppard  and 
Houck.13 

The  most  convenient  and  useful  alkali  for  this  purpose  is  am- 
monia. In  an  experiment  comparing  the  treatment  of  film  in  am- 
monia after  fixation  in  a  potassium  alum  bath  with  fixation  in  a 
chrome  alum  bath,  the  results  showed  that  the  ammonia  treatment 
has  an  effect  equal  to  that  of  chrome  alum  in  permitting  hypo  re- 
moval. Super-^  Negative  Film,  Type  1232,  was  fixed  in  F-25, 
rinsed  for  2  minutes,  bathed  in  0.03  per  cent  ammonia  solution 
(pH  —  10.2,  and  washed  with  film  samples  fixed  in  F-25  and  in 
the  chrome  alum  F-23  bath.  The  results  are  given  in  Table  VI. 

TABLE  VI 

Effect  of  Dilute  Ammonia  Bath  After  Fixing  on  Hypo  Removal 

Hypo  Content  (Mg  per  Sq-In) 
Fixing  Bath  Treatment  5  Min  15  Min        30  Min 

Potassium  alum  ( F-25}  0 . 56  0 . 24        0 . 08 

Potassium  alum  (F-25}          0.03%  Ammonia  Nil  Nil  Nil 

Chrome  Alum  (F-23}  0.005  Nil  Nil 

When  film  samples  were  washed  in  the  same  apparatus  with  the  /?H 
of  the  water  maintained  at  approximately  £H-9.5,  the  rate  of  removal 
was  almost  as  great  as  indicated  in  Table  VI. 

TABLE  VII 

Effect  of  Ammonia  on  Degree  of  Hardening  (Emulsion  1232} 

Concentration  of  Melting  Point  (°F) 

Ammonia  2  Min  Bathing  5  Min  Bathing          10  Min  Bathing 

(%) 

0.56  161  140  100 

0.28  174  166  126 

0.14  182  176  154 

0.07  186  182  172 

0.03  194  192  190 

0.00  210  210  210 

The  hardness  of  the  gelatin  film  is  affected  by  this  alkaline  treat- 
ment but  not  to  any  serious  extent  if  the  concentration  of  alkali 
is  not  excessive.  From  Table  VII  it  is  seen  that  ammonia  used 


July,  1943] 


REMOVAL  OF  HYPO  AND  SILVER  SALTS 


35 


at  the  concentration  recommended  (0.03%)  is  entirely  satisfactory, 
at  least  for  times  of  treatment  up  to  10  minutes. 

(b)  Temperature  of  Wash  Water. — Previous  studies  on  the  removal 
of  hypo  by  washing  have  shown  that  the  rate  of  removal  increases 
appreciably  as  the  temperature  of  the  wash  water  increases.2  The 
curves  in  Fig.  12  for  Eastman  Motion  Picture  Super-XX  Panchro- 
matic Negative  Film,  Type  1232,  are  representative  of  the  curves  for 


15  30  40 

-HME  OP  WASHING -MINUTES 


FIG.  12.  Effect  of  temperature  on  rate 
of  removal  of  hypo.  Eastman  Motion 
Picture  Super-JOT  Panchromatic  Negative 
Film,  Type  1232. 

the  entire  series  of  films  tested.  It  is  evident  that  an  increase  in  the 
washing  temperature  produced  an  increase  in  the  rate  of  removal 
of  hypo  from  the  film  and  that  the  effect  is  greatest  for  the  shorter 
washing  times.  For  example,  an  increase  in  temperature  of  the 
wash  water  from  41°  to  75  °F  doubled  the  rate  of  removal  of  hypo 
for  a  15-minute  washing  time,  the  actual  quantity  being  reduced 
from  0.32  mg  per  sq-in  to  0.16  mg  per  sq-in.  Such  differences  in 
the  rate  of  removal  are  of  practical  significance,  especially  where 
the  available  time  for  washing  is  short  and  the  temperature  of  the 
water  supply  is  low. 


36  CRABTREE,  EATON,  AND  MUEHLER         [j.  s.  M.  P.  E. 

(c)  Chemical  Constituents  in  Water. — The  degree  of  purity  of  the 
water  supply  is  of  primary  importance  when  washing  photographic 
materials  for  archival  purposes  because  it  is  obviously  useless  to 
treat  photographic  images  in  water  containing  chemicals  which  are 
harmful  to  the  image. 

Distilled  water,  rain  water,  or  water  from  melted  ice  or  snow  is 
satisfactory.  Many  city  water  supplies  are  suitable  but  their 
composition  should  be  checked  carefully  before  use.  The  most 
common  impurities  in  water  may  be  grouped  as  follows:14 

(1)  Dissolved  salts  which  produce  hardness  such  as  bicarbonates, 
chlorides,  and  sulfates  of  calcium  and  magnesium.     These  are  not 
dangerous  from  the  standpoint  of  effect  on  the  image  but  as  a  visible 
scum  which  reduces  the  transparency  of  the  film.     It  is  important, 
therefore,  to  squeegee  the  film  thoroughly  just  previous  to  drying. 

(2)  Suspended  matter  which  may  consist  of  mud,  iron  rust,  free 
sulfur,    decayed  vegetable  matter,    or  biological   growths.     These 
should  be  removed  by  filtration. 

(3)  Dissolved  extracts  which  are  usually  colored  yellow  or  brown. 
Such  coloring  matter  often  becomes  mordanted  to  the  film  or  paper 
which  has  been  hardened  with  alum  causing  stains  but  this  staining 
may  frequently  be  overcome  by  fixing  in  a  non-hardening  fixing 
bath  free  from  alum. 

(4)  Dissolved  gases  such  as  air,  carbon  dioxide,  and  hydrogen 
sulfide.     Waters  containing  hydrogen  sulfide  are  also  apt  to  contain 
colloidal  sulfur  which  is  retained  by  the  film  and  ultimately  reacts 
with  the  image. 

(2)  Effect  of  Turnover  of  Water. — A  good  washing  system  was  a 
prerequisite  to  this  investigation  and,  although  no  detailed  con- 
sideration of  the  mechanics  of  washing  is  included  here,  it  seemed 
advisable  to  consider  in  a  general  way  the  factors  involved  in  washing 
in  order  (a)  to  insure  the  most  effective  washing  conditions  in  an 
experimental  washing  device,  and  (b)  to  establish  the  general  con- 
ditions to  be  satisfied  in  practice.  The  rate  of  renewal  of  water  at 
the  surface  of  the  material  being  washed  has  been  claimed  an  im- 
portant factor. 

The  turnover  is  dependent  upon  the  input  of  water  and  the  di- 
mensions of  the  vessel.  In  very  small  washing  units,  such  as  small 
diameter  tubes,  very  shallow  tanks,  etc.,  the  turnover,  with  sufficient 
input,  provides  adequate  agitation  for  the  body  of  liquid.  It  is 
practical  to  use  an  input  great  enough  to  provide  both  turnover 


July,  1943  ]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  37 

and  agitation.  On  the  other  hand,  in  large  tanks,  the  agitation  that 
can  be  produced  by  inflow  usually  is  negligible,  giving  rise  to  a  more 
or  less  stagnant  condition  in  parts  of  the  liquid. 

It  is  apparent  that  the  renewal  of  water  at  the  surface  of,  say,  a 
strip  of  film  can  be  made  adequate  in  the  small  washing  units  by  using 
sufficient  input  but  in  the  large  tanks  only  by  the  use  of  mechanical 
agitation. 

During  the  removal  by  washing  of  hypo  from  photographic  prod- 
ucts the  rate  of  diffusion  of  hypo  from  the  film  to  the  water  depends 
on  the  difference  in  concentration  of  hypo  in  the  film  and  in  the  water. 
The  rate  of  washing  is  therefore  greatest  when  the  concentration 
of  hypo  in  the  water  is  at  a  minimum,  while  the  rate  can  be  zero 
when  the  concentration  in  the  water  is  sufficiently  great. 

In  order  to  obtain  the  greatest  rate  of  washing  as  indicated  above, 
it  is  important  to  employ  maximum  turnover  and  maximum  rate  of 
renewal  at  the  film  surface. 

The  experimental  washing  device  used  in  this  investigation 
fulfilled  thex  conditions  outlined.  The  turnover  was  55  times  the 
capacity  per  hour  and  the  agitation  was  sufficient  to  overcome 
stagnation.  A  decrease  in  input  increased  the  time  required  to  re- 
move a  given  amount  of  hypo  from  the  film  but  the  turnover  and 
degree  of  agitation  were  always  adequate. 

Curve  A  in  Fig.  2  demonstrates  the  effect  of  different  "inputs" 
on  the  removal  of  hyp£>  from  15-inch  strips  of  35-mm  film  in  a  given 
washing  time  when  suspended  in  a  vertical  glass  tube  of  lV2-inch 
diameter.  This  system  was  characterized  by  the  fact  that  the 
turnover  caused  adequate  agitation  and  that  renewal  at  the  surface 
approached  a  maximum. 

Samples  of  Eastman  Motion  Picture  Release  Positive  Film, 
Type  1301,  and  Super-J^Z  Panchromatic  Negative  Film,  Type  1231, 
were  processed  and,  after  fixing,  were  washed  in  tanks  of  large 
volume  as  compared  with  the  tube  described  above.  At  a  given 
input  the  tests  were  duplicated  with  and  without  air  agitation,  the 
results  indicating  that  air  agitation  of  the  wash  water  greatly  in- 
creased the  rate  of  removal  of  hypo  owing  to  the  rapid  renewal  of 
water  at  the  surface  of  the  film. 

A  third  system  considered  was  spray  washing.  Since  in  this 
case  no  contaminated  water  could  accumulate  on  the  film,  it  was 
evident  that  maximum  turnover,  agitation,  and  renewal  at  the 


38  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 

surface  were  approached.     The  tests  indicated  that  such  a  system 
was  very  effective  in  the  removal  of  hypo. 

WASHING  OF  PAPER  PRINTS 

Photographic  paper  prints,  even  after  careful  processing,  are 
more  susceptible  to  deterioration  (i.  e.,  fading)  than  film  negatives 
or  positives.  Two  factors  influence  this  apparent  susceptibility, 
namely,  (1)  the  high  degree  of  reflection  of  the  print  reveals  very 
slight  changes  in  the  silver  image,  and  (2)  the  structure  of  the  print 
is  such  that  more  hypo  is  retained  per  unit  area  than  by  an  equivalent 
area  of  film  following  the  same  fixing  and  washing  procedure. 

The  hypo  contents  of  commercially  processed  prints  vary  consider- 
bly  depending  upon  the  type  of  washing  equipment  used  but,  in 
general,  they  contain  quantities  indicated  in  Table  I. 

An  earlier  paper2  discussed  in  detail  the  removal  of  hypo  following 
fixation  in  fresh  fixing  baths  and  it  was  recommended  that,  in  order 
to  insure  the  complete  elimination  of  hypo,  single-  and  double-weight 
prints  be  washed  for  one-half  hour  to  one  hour,  respectively,  in 
water  at  60°  to  70 °F  and  then  be  treated  in  a  hydrogen  peroxide- 
ammonia  eliminator. 

The  effect  of  exhaustion  of  the  fixing  bath  on  the  removal  of  silver 
and  hypo  was  not  considered,  although  the  silver  thiosulfates  re- 
tained in  the  print  are  largely  responsible  for  the  yellowing  of  the 
highlights  of  faded  prints.  The  experiments  outlined  above  for 
film  were  therefore  repeated  with  photographic  paper  and  it  was 
found  that  the  removal  of  the  last  traces  of  hypo  and  silver  from 
prints  is  more  complicated  than  in  the  case  of  films.  In  general, 
photographic  papers  consist  of  (1)  the  paper  base,  (2)  a  baryta  coating, 
and  (3)  an  emulsion  coating,  all  of  which  retain  hypo  and  silver. 

Regular  photographic  papers  were  compared  with  a  paper  having 
the  base  and  baryta  coating  waterproofed  and  coated  with  a  chloride 
type  of  emulsion.  The  results  showed  that  both  hypo  and  silver 
were  more  readily  removed  from  such  a  waterproofed  paper  by  wash- 
ing than  from  the  regular  paper,  indicating  that  the  normal  baryta 
coating  and  paper  base  tend  to  retain  a  considerable  quantity  of 
hypo  and  silver. 

Experiments  with  non-waterproofed  paper  base  alone  bathed 
in  plain  hypo,  fresh  and  exhausted,  showed  that  for  a  given  washing 
time  the  quantity  of  hypo  and  silver  remaining  in  the  paper  base 
increased  with  the  time  of  treatment  in  the  hypo  bath  and  that 


July,  1943  ]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  39 

the  last  traces  of  hypo  and  silver  could  not  be  removed  by  washing. 
With  a  potassium  alum  bath  (F-5),  more  hypo  was  retained  than  with 
a  non-hardening  bath  (F-24).  This  difference  was  not  due  to  the 
presence  of  alum  but  to  the  difference  in  pH  of  the  two  baths,  as 
evidenced  by  the  fact  that  the  hypo  content  was  the  same  when 
F-5  was  compared  with  F-5  minus  alum  and  adjusted  to  the  same 
/>H.  Ammonia  baths  caused  an  increase  in  the  rate  of  removal  but 
an  excessive  time  of  treatment  was  necessary  to  bring  about  com- 
plete removal. 

Baryta  coatings  on  both  regular  paper  base  and  on  glass  were 
tested.  With  the  "paper  plus  baryta,"  more  hypo  was  retained 
than  with  the  paper  base  alone.  To  determine  the  role  of  the 
baryta,  coatings  on  glass  were  compared  with  gelatin  coatings  on 
glass. 

In  a  plain  hypo  solution  the  baryta  coating  retained  hypo  which 
was  not  readily  removed  by  washing.  When  a  potassium  alum 
fixing  bath  was  used,  a  much  greater  quantity  of  hypo  was  retained 
by  the  baryta  which  could  not  be  removed  by  prolonged  washing, 
but  the  increased  hypo  retained  under  the  same  conditions  by  the 
plain  gelatin  was  washed  out.  Both  the  baryta  and  gelatin  coatings 
retained  hypo  and  silver  from  an  exhausted  fixing  bath  when  the  pH 
was  maintained,  but  when  the  pH  increased  during  exhaustion  to 
5.5  the  baryta  retained  slightly  less  hypo  and  silver  while  the  gelatin 
did  not  retain  any.  It  is  apparent,  therefore,  that  the  removal  of 
hypo  and  silver  from  baryta  is  not  affected  by  changes  in  the  £H 
of  the  fixing  bath  in  the  range  4.0  to  5.6  to  the  same  degree  as  the 
removal  from  gelatin. 

A  dilute  ammonia  solution,  however,  promoted  the  removal  of 
hypo  and  silver  from  either  the  baryta  or  the  gelatin  coatings  while 
a  second  fixing  bath  removed  the  silver. 

The  presence  of  potassium  alum  in  the  fixing  bath  and  changes 
in  />H  of  the  fixing  bath  effected  similar  changes  in  the  rate  of  re- 
moval of  hypo  from  the  paper  emulsion  coated  on  the  waterproofed 
base  (with  baryta  coating)  as  obtained  with  Eastman  Motion  Picture 
Positive  Film,  Type  1301. 

When  the  regular  paper  base  plus  baryta  plus  emulsion  (regular 
photographic  paper)  was  treated  in  non-hardening  (F-24)  and 
hardening  (F-5)  fixing  baths  both  at  the  original  and  increased  pH 
values,  it  was  found  that  (1)  />H  values  in  the  range  of  4.0  to  5.6  had 
little  effect  on  the  rate  of  removal  of  hypo  and  silver,  (2)  the  rate 


40  CRABTREE,  EATON,  AND  MUEHLER        tf.  S.  M.  P.  E. 

of  removal  was  greater  after  fixing  in  F-24  as  compared  with  F-5, 
only  during  the  early  stage  of  washing,  and  (3)  small  amounts  of 
residual  hypo  and  silver  in  the  base  and  baryta  coating  were  not 
removed  by  very  prolonged  washing.  Adsorption  of  silver  com- 
menced with  the  first  paper  prints  processed. 

Bathing  in  ammonia  solutions  caused  the  complete  removal  of 
hypo  and  silver  from  photographic  paper  only  after  very  long  times 
of  treatment  and,  therefore,  could  not  be  considered  adequate  in  the 
normal  processing  of  prints. 

When  residual  silver  is  mordanted  it  is  apparently  always  combined 
with  a  certain  amount  of  thiosulfate.  If  these  silver  complexes 
remain  in  the  print,  especially  in  the  absence  of  excess  hypo,  early 
decomposition  to  silver  sulfide  may  result.  This  condition  may  exist 
even  after  the  hypo  has  been  removed  with  the  hypo  eliminator2 
because,  following  fixation  in  a  moderately  exhausted  bath,  the  hypo 
eliminator  does  not  attack  the  silver  complex  as  readily  as  it  does 
hypo.  With  increasing  times  of  treatment  in  the  eliminator  the  quan- 
tity of  residual  hypo  and  silver  decreases  until  eventually  they 
are  completely  removed  but  such  treatment  is  usually  too  severe 
for  the  finished  print. 

The  most  practical  and  efficient  method  of  removing  the  last 
traces  of  both  silver  and  hypo  from  prints  is  to  employ  two  or  three 
successive  fixing  baths.  A  second  bath  is  imperative  in  any  fixing 
operation  and  a  fresh  third  bath  is  imperative  in  the  preparation 
of  permanent  prints  when  the  residual  silver  content  must  be  zero. 
The  residual  hypo  is  then  removed  by  means  of  the  hypo  eliminator. 

In  the  case  of  films,  as  shown  in  Fig.  11,  silver  was  retained  in  the 
film  (with  exhaustion)  when  the  fixing  bath  or  baths  were  main- 
tained at  a  pH  value  below  4.9  but  was  not  retained  if  the  pH  was 
higher  than  4.9.  A  similar  study  made  with  prints  indicated  a 
retention  of  silver  (to  a  lesser  degree)  when  the  baths  were  main- 
tained below  pYL  =  4.9  but,  at  pH  values  above  4.9,  the  nature  of 
the  fixing  bath  had  very  little  or  no  effect  on  the  removal  of  silver 
from  the  prints.  Fig.  13  shows  the  relative  increase  in  the  silver 
content  of  the  baths  and  prints  when  two  F-5  fixing  baths  at  pH 
=  4.1  were  used.  It  is  evident  that  sixty  to  seventy  8  X  10-inch 
prints  per  gallon  can  be  processed  free  of  residual  silver  by  using  this 
combination  of  fixing  baths. 

In  general,  the  effects  of  (1)  the  change  of  pH  of  the  fixing  bath, 
(2)  the  use  of  a  dilute  ammonia  solution,  and  (3)  the  combinations 


July,  1943] 


REMOVAL  OF  HYPO  AND  SILVER  SALTS 


41 


of  fixing  baths  recommended  for  the  removal  of  silver  and  hypo 
from  film  were  of  little  practical  value  with  prints  because  of  the 
mordanting  effects  of  the  baryta  coating  and  paper  base.  However, 
chrome  alum  fixing  baths,  which  may  be  used  if  the  resulting  slight 
green  stain  can  be  tolerated,  and  plain  hypo  baths  provide  conditions 
for  a  very  marked  increase  in  the  rate  of  removal  of  hypo  and  silver 
by  washing.  This  increase  in  the  rate  of  removal  is  obtained,  how- 
ever, only  during  the  first  few  minutes  of  washing.  With  exhausted 
chrome  alum  baths  traces  of  both  silver  and  thiosulfate  remain  after 
prolonged  washing  of  prints  as  in  the  case  of  films. 


fe 

it 

t       , 


O  2O          4O          feO          8O          IOO          I2O         I4O         IfeO        I8O 

DEGREE  OF  EXHAUSTION    8XIO  INCH  PRINTS  PER  GALLON 

FIG.   13.  ^Effect  of  exhaustion  on  concentration  of 
silver  in  first  and  second  fixing  baths  and  in  paper  prints 
fixed  in  these  baths.     Azo  F-3.     Kodak  Fixing  Bath  F-5. 
H  maintained.     Prints  washed  20  minutes. 


THEORETICAL  DISCUSSION 

When  silver  halides  are  fixed  out  from  an  emulsion  by  a  sodium 
(or  ammonium)  thiosulfate  (hypo)  fixing  bath,  they  are  undoubtedly 
converted  to  complex  silver  thiosulfates,  the  exact  composition  of 
the  complexes  varying  with  the  degree  of  exhaustion  of  the  bath. 
The  work  of  Bassett  and  Lemon,15  using  silver  nitrate  solution, 
would  indicate  that  the  maximum  ratio  of  silver  to  sodium  in  the 
complex  formed  in  sodium  thiosulfate  solutions  rich  in  silver  is 
represented  by  the  formula  NaAgs^OsV  On  the  other  hand, 
Baines,16  using  silver  carbonate,  found  that  the  formula  of  the 
complex  in  thiosulfate  solutions  rich  in  silver  is 


42  CRABTREE,  EATON,  AND  MUEHLER         [J.  s.  M.  P.  E. 

References  are  cited  by  Baines  to  show  the  general  agreement  by 
other  workers  on  the  composition  of  this  complex. 

Assuming  that  the  initial  ratio  of  silver  to  sodium  in  the  complex 
approaches  a  value  of  3:1  or  1:1,  this  ratio  is  quickly  changed  by 
virtue  of  dilution  by  the  excess  fixing  bath  diffusing  through  the 
emulsion. 

Much  of  the  published  literature  states  that  the  first  reaction  is 
to  form  a  difficultly  soluble  complex  and  that  on  prolonged  fixation 
this  is  changed  to  a  more  soluble  one.  However,  it  is  now  apparent 
that  when  the  milkiness  of  a  pure  silver  bromide  emulsion  has  dis- 
appeared, the  silver  halide  has  been  rendered  completely  soluble 
and  capable  of  being  washed  out. 

This  removal  of  silver  complexes  takes  place  in  two  stages,  namely, 
(1)  the  complex  silver  ions  diffuse  out  of  the  gelatin  film  while  in 
the  fixing  bath,  and  (2)  diffusion  of  both  complex  silver  ions  and 
thiosulf ate  ions  takes  place  in  the  wash  water. 

The  washing  of  photographic  materials  represented  by  (2\  above 
is  considered  to  be  an  exponential  process  provided  there  are  no 
impediments  to  normal  diffusion  of  the  hypo  from  the  gelatin  layer. 
Hickman  and  Spencer7  reported  a  divergence  from  the  exponential 
curve,  or  a  "tailing  off"  of  the  curve,  when  a  potassium  alum  harden- 
ing bath  was  used  prior  to  fixation,  and  stated  that  potassium  alum 
retards  the  washing  out  of  an  electrolyte  (not  identified) . 

The  washing  data  in  this  investigation,  when  plotted  logarith- 
mically, verified  the  exponential  process  and  the  "tailing  off"  of 
the  curves  in  some  cases.  When  potassium  alum  fixing  baths  were 
used  the  divergence  from  the  exponential  was  very  marked  but 
with  chrome  alum  baths,  no  "tailing  off"  occurred.  However,  with 
exhausted  potassium  and  chrome  alum  baths  appreciable  "tailing 
off"  occurred  as  a  result  of  the  retention  of  a  complex  silver  thio- 
sulfate  ion. 

With  photographic  papers  the  divergence  from  the  exponential 
was  always  large  because  of  the  effect  of  the  baryta  coating  and 
the  paper  base. 

The  primary  concern  in  this  study  was  the  removal  of  the  last 
traces  of  thiosulfate  and  silver  thiosulfate  ions  (which  caused  the 
"tailing  off"  of  the  exponential  washing  curves)  retained  by  the 
material  even  after  long  times  of  washing. 

The  retention  of  very  small  quantities  of  hypo  and  silver  which 
in  some  cases  are  not  removed  by  prolonged  washing  is  undoubtedly 


July,  1943]          REMOVAL  OF  HYPO  AND  SILVER  SALTS  43 


the  result  of  adsorption  of  the  thiosulfate  and  silver  ions.  Gelatin 
as  an  amphoteric  electrolyte  does  not  combine  with  salts  but  with 
ions.  At  £H  values  lower  than  the  isoelectric  point  (/>H  =  4.9) 
the  gelatin  becomes  more  positively  charged  and  has  a  greater 
attraction  for  anions,  such  as  the  thiosulfate  ion  or  a  complex  silver 
thiosulfate  ion,  while  the  converse  is  the  case  at  £H  values  greater 
than  the  isoelectric  point  when  the  attraction  diminishes  for  anions 
but  increases  for  cations.13  The  conditions  under  which  thiosulfate 
and  complex  silver  thiosulfate  ions  are  adsorbed  and  the  conditions 
for  their  subsequent  removal  by  washing  are  outlined  in  Table 
VIII. 

(1)  Adsorption  of  Thiosulfate  and  Silver  Thiosulfate  Ions. 
—The  adsorption  is  governed  by  the  following  factors : 

(a)  The  pH  of  the  Wash  Water. — Since  the  £H  of  the  wash  water 
is  usually  above  7.0,  it  is  evident  that  the  />H  of  a  film  fixed  in  any 
fixing  bath  at  a  £H  lower  than  the  isoelectric  point  will  slowly  ap- 
proach the  isoelectric  point  of  the  gelatin  during  washing,   thus 
permitting  a  greater  rate  of  removal  of  adsorbed  anions  such  as 
thiosulfate  ions.     The  higher  the  pH  of  the  fixing  bath  the  greater 
will  be  the  apparent  rate  of  removal  because  there  is  less  ion  ad- 
sorbed by  gelatin  from  the  higher  £H  fixing  baths. 

(b)  The  Composition,  Degree  of  Exhaustion,  and  pH  of  the  Fixing 
Bath. — With  fresh  potassium  alum-boric  acid  fixing  baths,  the  time 
required  to  remove  completely  the  thiosulfate  ion  was  much  longer 
than  with  non-hardening  baths  but  an  increase  in  the  £H  of  the 
fixing  bath  to  />H  =  5.0  produced  an  apparent  increase  in  the  rate  of 
removal  of  the  thiosulfate  ion. 

Assuming  that  the  hardening  of  gelatin  by  alum  is  due  to  the 
precipitation  of  alumina  or  a  compound  with  gelatin  which  will  be 
termed  an  "alumina  complex,"  it  is  apparent  that  this  complex 
adsorbs  thiosulfate  ion  in  considerable  excess  over  the  amount  ad- 
sorbed by  gelatin  alone. 

With  used  potassium  alum-boric  acid  hardening  fixing  baths,  the 
last  traces  of  thiosulfate  and  silver  were  not  washed  out  when  the 
/>H  was  maintained  (/>H  =  4.1  with  F-5)  but  were  easily  removed 
when  the  $H  increased  to  about  5.0  during  the  exhaustion.  These 
results  would  tend  to  indicate  that  the  silver  and  thiosulfate  were 
adsorbed  together  as  a  negatively  charged  complex  ion  which  washed 
from  the  film  when  the  pR  was  sufficiently  high.  The  fact  that  this 
complexion  was  not  removed  by  extended  washing  at  low  pH  values, 


TABLE  Vin 

The  Adsorption  and  Subsequent  Removal  of  Ions  from  Processed  Photographic  Film 

and  Paper 
Film 


Type  of  Fixing  Bath 

Potassium  alum  baths,  e.  g., 

F-5,  F-10,  F-25 
(a)     Fresh 


Mordanted  Ion 


s2or 


(6)     Exhausted 


S203= 


Chrome  alum  baths, 

F-16,  F-23 
(a)     Fresh 
(6)     Exhausted 


Bisulfite  hypo,  e.  g.t  F-24 
(a)     Fresh 


None 

[Agz(S2O3)/- 


Paper 

S203- 


Exhausted 


Chrome  alum  baths 
Potassium  alum  baths 

(a)    Fresh 

(6)     Exhausted  / 


As  with  F-24 


Means  of  Removal 


(1)  Increase  temperature  of 
wash  water  and  agita- 
tion of  water 

(2}  Increase  pH.  of  fixing  bath 
to  value  above  isoelec- 
tric  point  of  gelatin, 
e.  g.,  use  F-6 

(3)  Use  dilute  ammonia  solu- 
tion (0.03%) 

(1)  Increase   />H    above   iso- 

electric    point,     e.    g., 
use  F-6 

(2)  Use  any  second  or  third 

fixing  bath 

(1)  Use  a  second  fixing  bath 

with  pH  above  isoelec- 
tric   point,    e.   g.,    F-6 

(2)  Use  a  second  fixing  bath 

minus  potassium  alum 


(1)  Increase  pR  of  bath  to 

value    above    5.0    (no 
hardening  at  this  value) 

(2)  Use  a  second  or  third  fix- 

ing bath ;  chrome  alum 
or  F-24 


(1)  Increase    temperature    of 

wash  water 

(2)  Increase      agitation      of 

prints  in  water 
(5)  Peroxide-ammonia    hypo 

eliminator 
[Ag-e(S2O3)vn~]         (1)  Any  second  or  third  fixing 

bath  followed  by 
Hypo  eliminator 


(2} 

As  with  F-24 


As  with  F-24  but  } 

much     greater  \  As  with  F-24 
quantities 


REMOVAL  OF  HYPO  AND  SILVER  SALTS  45 

whereas  thiosulfate  ion  alone  was  removed  (as  with  a  fresh  bath), 
would  suggest  a  difference  in  the  mechanism  of  the  adsorption  of 
plain  thiosulfate  ions  as  compared  with  silver  thiosulfate  ions  when 
adsorbed  to  the  alumina  complex. 

The  complex  silver  thiosulfate  ion  was  adsorbed  from  baths  at 
constant  pH  below  pH  =  4.7  only  if  the  degree  of  exhaustion  cor- 
responded to  a  value  of  at  least  200  feet  of  motion  picture  negative 
film  per  gallon.  Since  the  composition  of  the  sodium  silver  thio- 
sulfate complexes  in  a  fixing  bath  undoubtedly  varies  with  the  degree 
of  exhaustion,  it  is  quite  likely  that  for  degrees  of  exhaustion  above 
the  200  feet  per  gallon  stage  the  composition  of  the  fixing  bath  is 
such  that  it  can  no  longer  affect  the  complexes  in  the  emulsion 
sufficiently  to  prevent  the  adsorption  of  a  complex  silver  thiosulfate 
ion  by  the  alumina  hardening  complex.  This  contention  is  sup- 
ported by  the  fact  that  any  adsorbed  complex  is  removed  completely 
with  a  fresh  hypo  solution.  If  the  degree  of  exhaustion  and,  there- 
fore, the  concentration  of  silver  in  the  bath  increases,  it  can  be  as- 
sumed that  the  degree  of  adsorption  of  silver  to  the  alumina  complex 
increases  and  likewise  that  the  rate  of  diffusion  of  silver  from  the 
gelatin  decreases. 

Whether  or  not  the  composition  of  the  adsorbed  complex  silver 
thiosulfate  ion  changes  with  increasing  degrees  of  exhaustion  is  not 
known  but  preliminary  analyses  have  indicated  that  up  to  a  degree 
of  exhaustion  corresponding  to  500  feet  of  Eastman  Motion  Picture 
Panchromatic  Negative  Film,  Type  1232,  per  gallon,  the  ratio  of 
silver  to  thiosulfate  in  the  residual  adsorbed  complex  ion  is  probably 
one  silver  atom  to  one  thiosulfate  radical. 

When  comparing  the  adsorption  properties  of  chrome  alum  with 
potassium  alum-hardened  gelatin,  in  the  case  of  a  fresh  fixing  bath 
having  a  low  or  negligible  silver  content,  the  thiosulfate  ion  is  ap- 
parently not  mordanted  to  the  chromium  hardening  complex  but 
is  very  appreciably  adsorbed  to  the  alumina  complex.  However, 
when  the  silver  concentration  in  the  fixing  bath  reaches  a  critical 
value  corresponding  to  a  degree  of  exhaustion  of  200  feet  of  the 
Negative  Film,  Type  1232,  per  gallon,  traces  of  silver  and  thio- 
sulfate are  adsorbed  both  by  the  chromium  and  alumina  complexes. 
After  chrome  alum  fixation  the  silver  and  thiosulfate  concentrations 
decrease  on  prolonged  washing  but  remain  constant  after  potassium 
alum  fixation,  unless  the  ^>H  of  the  fixing  bath  or  wash  water  is  in- 
creased. These  facts  would  indicate  a  difference  in  the  mechanism 


46  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 


of  adsorption  of  the  thiosulfate  ion,  [Ag^^Os)  yW]  .  With  non-harden- 
ing fixing  baths  (F-24),  both  silver  and  thiosulfate  likewise  wash 
out  more  readily  when  the  £H  is  allowed  to  increase  as  compared 
with  a  maintained  pH  of  5.6. 

(c)  The  Time  of  Fixation.  —  An  emulsion  is  considered  completely 
fixed  when  it  is  possible  to  reduce  the  non-developed  silver  content 
to  zero  by  subsequent  washing.  With  Eastman  Motion  Picture 
Release  Positive  Film,  Type  1301,  on  prolonged  washing,  it  was 
possible  to  remove  the  silver  completely  after  fixing  for  the  "time 
to  clear"  but  a  much  shorter  washing  time  was  adequate  if  the  film 
was  fixed  for  the  usually  recommened  twice  the  apparent  "time  to 
clear"  in  a  non-hardening  fixing  bath.  However,  when  a  potassium 
alum  fixing  bath  was  used  complete  fixation  was  obtained  only  after 
three  to  four  times  the  apparent  time  to  clear. 

Exhaustion  of  a  plain  hypo  bath  (F-24)  extended  the  washing  time 
but  exhaustion  of  potassium  alum  baths  prevented  complete  fixa- 
tion even  when  the  "time  to  clear"  factor  was  much  greater  than 
two.  An  increase  in  the  />H  of  the  fixing  bath,  however,  facilitated 
washing. 

On  the  other  hand,  films  such  as  Eastman  Motion  Picture  Super- 
XX  Panchromatic  Negative  Film,  Type  1232,  containing  silver 
iodide,  required  a  factor  of  four  times  the  "time  to  clear"  followed 
by  a  washing  time  longer  than  was  previously  thought  necessary 
for  the  complete  removal  of  silver.  An  increased  />H  was  also 
necessary  when  using  exhausted  potassium  alum  fixing  baths  to  ob- 
tain complete  fixation. 

When  fixing  times  of  four  to  ten  times  the  "time  to  clear"  were 
used  with  Eastman  Motion  Picture  Positive  Film,  Type  1301,  and 
Super-  JOT  Negative  Film,  Type  1232,  in  fresh  and  exhausted  potas- 
sium alum  fixing  baths,  two  facts  were  evident,  namely,  (1)  the 
the  quantities  of  residual  hypo  and  silver  in  the  Positive  Type  1301 
film  increased  appreciably,  and  (2)  no  measurable  increase  in  the 
quantities  of  residual  hypo  and  silver  occurred  with  the  Super-XX 
Negative  Film,  Type  1232. 

These  effects  are  closely  related  to  the  effect  of  time  of  fixation  on 
the  degree  of  hardening  of  the  gelatin  film.  As  the  degree  of  harden- 
ing increases  with  time,  the  concentration  of  alumina  in  the  gelatin 
increases  and  this,  in  turn,  adsorbs  an  increasing  quantity  of  thio- 
sulfate ion  or  of  a  complex  silver  thiosulfate  ion  depending  upon  the 
condition  of  the  bath. 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  47 

The  hardening  of  gelatin  by  chrome  alum  is  more  rapid  than  by 
potassium  alum.  The  fact  that  no  further  adsorption  of  complex 
silver  thiosulfate  ion  occurred  on  prolonged  fixation  would  also 
indicate  that  maximum  hardening  was  attained  in  a  relatively 
short  time. 

It  has  been  suggested  that  the  silver  image,  in  some  cases,  may 
retain  small  amounts  of  hypo  even  though  the  highlights  are  free 
from  hypo.  Most  developed  images  on  film  and  paper  contain 
a  trace  of  silver  sulfide  which  is  approximately  proportional  to  the 
silver  density  and  is  revealed  as  a  yellow  residual  image  on  treat- 
ment of  the  silver  image  with  Farmer's  reducer.17'  18>  19  Silver 
sulfide  under  certain  conditions  is  known  to  be  a  mordant  for  certain 
dyes  but  experimental  evidence  has  indicated  that  hypo  is  not 
mordanted.  The  sensitive  mercuric  chloride  test  for  film  and  the 
quantitative  determination  of  reducible  sulfur  in  print  images  have 
failed  to  reveal  any  difference  in  the  amounts  of  hypo  retained 
by  the  non -image  and  maximum  density  areas  of  film  or  print 
images. 

(2)  The  Desorption  of  Thiosulfate  and  Silver  Thiosulfate 
Ions. — The  adsorption  of  the  silver  thiosulfate  complex  may  be 
reversed  in  several  ways,  namely,  (a)  by  raising  the  £H  of  the  fixing 
bath  or  wash  water  or  both,  and  (b)  by  immersing  the  film  in  a  fresh 
fixing  bath  in  which  the  silver-ion  concentration  is  very  low  or  equal 
to  zero. 

Adsorbed  thiosulfate  ion  is  removed  by  raising  the  pH  of  the 
fixing  bath  or  wash  water,  or  both.  The  effect  of  the  pH  increase 
is  probably  to  change  the  nature  of  the  electrical  charges  on  the 
adsorbent  and  to  release  the  attraction  between  the  ions  and  the 
adsorbent. 

The  results  obtained  with  photographic  papers  may  also  be  ex- 
plained, for  the  most  part,  on  the  basis  of  an  assumption  of  adsorption 
of  both  thiosulfate  ion  and  complex  silver  thiosulfate  ion. 

In  the  case  of  the  emulsion  layer,  the  explanation  for  the  retention 
of  hypo  and  silver  by  film  is  directly  applicable.  However,  ad- 
ditional sorption  occurs  in  the  baryta  coating,  both  thiosulfate  ion 
and  complex  silver  thiosulfate  ion  being  sorbed,  but  the  changes 
in  ^>H,  effective  for  the  removal  of  these  ions  from  either  gelatin, 
the  alumina-gelatin  hardening  complex,  or  chrome  alum-gelatin 
complex,  were  not  great  enough  to  reverse  the  sorption  of  the  ions. 


48  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 

This  was  accomplished  only  after  bathing  in  ammonia  solutions 
for  long  times. 

The  hydrogen  peroxide-ammonia  hypo  eliminator  has  a 'twofold 
effect  on  thiosulfate  ions  adsorbed  to  papers,  namely,  (a)  the  high 
pH  of  the  solution  causes  desorption,  and  (b)  the  desorbed  ion  is 
oxidized  to  sulfate  which  is  harmless.  However,  the  adsorbed 
silver  complexes  do  not  respond  as  readily  to  pH  change,  as  men- 
tioned above,  while  there  is  probably  a  slow  reaction  between  the 
adsorbed  ion  and  the  peroxide-ammonia  solution.  These  silver 
complexes,  however,  are  very  readily  desorbed  in  hypo  solutions. 

TABLE  IX 

Suggested  Maximum  Permissible  Concentration  of  Hypo 

Commercial  Use  Archival  Use 

Films  (Mg  per  Sq-In)  (Mg  per  Sq-In) 

Eastman  Motion  Picture  Films 

Fine-Grain  Duplicating  Positive  Film,  0 . 02  0 . 005 

Type  1365 

Fine-Grain    Release    Positive    Film,  0.05  0.01 

Type  1302 

Super-JO"     Panchromatic     Negative  0.20  0.05 

Film,  Type  1232 

Photofinishers  and  Amateurs  0 . 15-0 .25*  0 . 05 
Eastman  X-Ray  Films 

No  screen  0.40-0.50*             .    0.10 

Blue  brand  0 . 25-0 . 40  *  0.05 

Industrial  type  A  0.15-0.25*  0.05 

Prints 

Double  Weight  0 . 20-0 . 25  Nil 

Single  Weight  0 . 10-0 . 15  Nil 

*  The  coatings  on  many  of  these  films  consist  of  either  (a)  emulsion  on  one  side 
and  gelatin  on  the  opposite  side,  or  (b)  emulsion  on  both  sides  fa-ray).  The 
above  data  represent  the  hypo  content  of  the  coating  on  only  one  side  of  the  film 
so  that  when  employing  the  mercuric  chloride  test  which  determines  the  total 
hypo,  the  values  in  the  above  table  should  be  doubled. 


PRACTICAL  RECOMMENDATIONS 

In  view  of  the  increasing  use  of  fine-grain  films  and  the  greater 
realization  of  the  necessity  for  the  perpetuation  of  photographic 
records,  very  careful  attention  should  be  given  to  the  operations  of 
fixing  and  washing. 

If  long  life  of  the  photographic  image  is  not  required,  it  is  un- 


July,  1943] 


REMOVAL  OF  HYPO  AND  SILVER  SALTS 


49 


necessary  to  remove  the  last  traces  of  silver  and  hypo,  so  that  in 
practice  we  may  have  two  requirements,  namely,  (1)  commercial 
fixing  and  washing  for  materials  with  an  expected  keeping  life  of  a 
few  decades  or  less,  and  (2)  "archival"  fixing  and  washing  which 
implies  complete  removal  of  all  substances  which  might  affect  either 
the  image  or  non-image  areas  during  long-time  storage. 


TABLE  x 

Suggested   Maximum  Permissible   Concentrations  of  Silver 

pH  of  Fixing  Bath  Maintained  below  4.9 

Single  Bath 

Films  Commercial  Use  Archival  Use 

(a)     Fixing  Bath          1 . 5  grams  per  liter  (twenty-  0.2    gram    per    liter    (two 

five  8  X  10-inch  films  per  8  X  10-inch  films  per  gal) 
gallon) 

0.01  mg  per  sq-in  Nil 


(6)     Film 

Paper 

(a)  Fixing  Bath 

(b)  Paper 

Films 

(a)     Fixing    Bath        6 . 0  grams  per  liter  (sixty  to    3.5  grams  per  liter  (forty 

8  X  10-inch  films  per  gal) 


0.3  gram  per  liter  (thirty  0.05  gram   per  liter   (five 

8  X  10-inch  prints  per  gal)  8  X  10-inch  prints  per  gal) 

0 . 005  mg  per  sq-in  Nil 

Two  Fixing  Baths 


No.  1 


seventy  8  X  10-inch  films 
per  gal) 
0 . 5-1 . 5  grams  per  liter  0 . 2  gram  per  liter 


Fixing    Bath 

No.  2 
(&)     Film  0.01  mg  per  sq-in  Nil 

Paper 

(a)  Fixing    Bath        2 . 0  grams  per  liter  (two  hun-     0 . 80  gram  per  liter  (seventy 

No.  1  dred  8   X    10-inch  prints        8   X    10-inch  prints  per 

per  gal)  gal) 

Fixing    Bath        0 . 3  gram  per  liter  0 . 05  gram  per  liter 
No.  2 

(b)  Paper  0 . 005  mg  per  sq-in  Nil 


Since  the  future  history  of  a  processed  negative  or  print  is  un- 
known, it  is  always  advisable  to  remove  completely  all  residual 
thiosulfates.  It  is,  however,  quite  possible  that  slight  tolerances 
may  be  permissible  even  with  archival  films  but  this  is  not  definitely 
known.  At  the  present  state  of  our  knowledge,  the  maximum 
tolerances  in  the  hypo  and  silver  content  of  films  and  prints  for 


50  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 

archival  and  commercial  purposes  given  in  Tables  IX  and  X  are 
suggested.  The  tables  also  show  the  suggested  maximum  permissible 
silver  concentrations  in  the  fixing  bath  or  baths.  This  is  important 
because  the  concentration  of  silver  in  the  bath  is  an  indication  of 
the  amount  of  silver  likely  to  be  retained  by  the  film  or  print  following 
good  washing. 

It  is  evident  from  Table  X  that  archival  films  and  prints  should 
contain  no  residual  silver  to  insure  that  the  non-image  areas  remain 
clear  indefinitely.  However,  a  slight  general  yellow  stain  does  not 
necessarily  impair  the  usefulness  of  a  film  or  print  so  that  for  com- 
mercial purposes  a  slight  quantity  of  residual  silver  can  be  tolerated. 

Two  general  types  of  photographic  paper  prints  should  be  con- 
sidered, namely,  (1)  the  fine-grain  chloride  type  contact  paper  and 
(2)  the  coarser-grain  bromide  type  enlarging  paper.  The  residual 
hypo  content  of  commercially  processed  fine-grain  prints  should 
not  exceed  the  values  given  in  Table  IX,  but  a  somewhat  greater 
quantity  of  residual  hypo  (approximately  50  per  cent  greater)  may 
be  tolerated  in  the  bromide  type  prints  because  the  coarser-grain 
images  are  not  so  susceptible  to  fading  as  the  fine-grain  images.2 
In  the  case  of  coarse-grain  bromides  for  archival  purposes,  0.05  to 
0.10  milligram  of  hypo  per  square-inch  could  probably  be  tolerated. 
This  hypo  content  may  be  obtained  without  the  use  of  a  hypo  elimi- 
nator if  the  prints  are  washed  for  two  hours  in  water  at  about  70  °F 
and  with  optimum  agitation.  It  must  be  remembered  that  other 
factors2  influence  the  permanence  of  negatives  and  prints  and  these 
have  been  considered  when  establishing  the  tolerances  given  above. 

The  processing  recommendations  given  below,  when  carefully 
followed,  should  effect  the  complete  removal  of  silver  and  hypo  from 
films  or  plates.  The  complete  removal  of  silver  and  hypo  from 
paper  prints  is  always  advised  and  complete  hypo  removal  may  be 
accomplished  by  the  use  of  the  peroxide-ammonia  hypo  eliminator2 
in  addition  to  the  recommendations  given  below.  However,  for  those 
whose  equipment  is  not  adequate  to  meet  these  demands,  appreci- 
able improvement  over  their  existing  methods  of  processing  can  be 
effected  by: 

(7)  Use  of  two  or  more  fixing  baths  to  reduce  the  silver  content. 

(2)  Judicious  choice  of  fixing  baths  to  reduce  both  silver  and 
hypo  contents. 

(3)  Adjusting  the  temperature  of  the  wash  water  to  65°  to  70°F 
to  accelerate  washing. 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  51 

(4)  Use  of  more  intensive  agitation  as  with  compressed  air. 

The  quantities  of  residual  hypo  and  silver  indicated  in  the  tables 
are  readily  obtained  under  good  fixing  and  washing  conditions  in  the 
usually  recommended  times  of  washing  and,  so  far  as  we  know, 
can  be  considered  to  be  safe,  from  a  permanence  viewpoint,  if  the 
films  and  prints  are  to  be  stored  under  average  conditions  in  temperate 
climates.  Under  tropical  or  accelerated  conditions,  it  is  necessary 
to  remove  all  the  silver  and  hypo  because  films  and  prints  containing 
amounts  of  hypo  much  less  than  those  given  may  fade. 

The  term  "commercial  washing"  has  been  used  to  denote  the  degree 
of  washing  necessary  to  insure  these  maximum  quantities  of  hypo 
in  both  films  and  prints. 

(1)  Tests  for  Silver  and  Hypo.— Satisfactory  tests  for  the  pres- 
ence of  silver  and  hypo  in  film  and  paper  are  outlined  below.  These 
have  been  modified  slightly  from  the  methods  outlined  on  p.  14  in 
order  to  meet  commercial  requirements. 

(a)  For  Silver. — A  drop  of  0.2  per  cent  sodium  sulfide  is  applied 
to  the  margin  of  the  dry  or  squeegeed  film  or  print  and  removed  after 
2  to  3  minutes  by  careful  blotting.     Any  coloration  produced  by 
formation  of  silver  sulfide  in  excess  of  a  just  visible  cream  tint  in- 
dicates the  presence  of  silver  in  the  film  or  paper.     For  careful 
control  a  satisfactory  standard  is  made  by  processing  a  blank  sheet 
of  film  or  paper  through  two  fresh  fixing  baths  and  a  control  test 
made  on  this  sheet.     The  stain  produced  is  an  indication  of  the 
stain  that  might  be  formed  in  the  highlights  with  adverse  storage 
conditions. 

(b)  For  Hypo. — Many  tests  have  been  proposed  in  the  literature 
for  the  determination  of  hypo  in  both  films  and  prints.     The  potas- 
sium permanganate  drip  test  is  in  common  use  for  testing  films  and 
prints  during  washing  but  its  sensitivity  is  limited  and  it  does  not 
determine  the  residual  hypo  in  the  washed  material. 

The  mercuric  chloride  test  described  on  p.  14  is  very  satisfactory 
for  use  with  either  dry  or  wet  film  samples  but  it  is  necessary  to  clip 
off  a  small  piece  of  the  film  to  be  tested  and  it  is  not  recommended 
for  measuring  the  total  hypo  content  of  prints.  This  test  is  particu- 
larly useful  when  films  are  being  prepared  for  archival  storage.  This 
reagent  is  poisonous,  should  be  handled  carefully,  and  washed  down 
the  drain  with  water  when  discarded. 

An  iodine  spot  test  has  been  suggested20  which  is  dependent  upon 
the  time  required  for  the  starch-iodine  spot  to  decolorize.  The 


52  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 

difficulty  in  application  of  the  test  was  the  reproducible  measurement 
of  the  volume  of  reagent  used  for  the  "spot"  which  must  be  constant. 
The  silver  nitrate  test  is  extremely  sensitive  and  especially  suited 
to  the  measurement  of  hypo  in  prints.  The  spot-testing  technique 
is  used  but  the  accuracy  of  the  test  does  not  depend  upon  the  volume 
of  reagent  because  the  silver  nitrate  and  hypo  react  in  situ  to  produce 
a  definite  quantity  of  silver  sulfide  since  a  great  excess  of  silver 
nitrate  is  used.  The  color  of  the  spot  varies  from  light  yellowish 
brown  to  dark  brown  depending  on  the  hypo  content.  The  test 
may  be  used: 

(1)  To  determine  whether  or  not  a  print  is  entirely  free  from  hypo 
following  the  use  of  the  peroxide-ammonia  hypo  eliminator,  when 
the  procedure  recommended  in  a  previous  paper  may  be  used.2     A 
dry  print  or  an  extra  wet  print  may  be  spot- tested  on  the  back  with 
silver  nitrate  and,  if  no  hypo  is  present,  no  yellow  stain  should 
appear.     The  excess  water  should  be  removed  from  a  wet  print  be- 
fore making  the  test. 

(2}  To  determine  the  approximate  quantity  of  residual  hypo  by 
matching  the  spot  with  one  of  a  series  of  spots  prepared  on  single- 
and  double-weight  prints  having  known  hypo  contents. 

(2)  The  Fixing  Process.— Complete  fixation  is  necessary  to  in- 
sure complete  removal  of  both  silver  and  thiosulfate  even  though  the 
washing  system  is  efficient,  and  therefore  the  photographer  needs 
to  know  (a)  what  bath  or  baths  insure  rapid  removal  of  hypo  and 
silver  thiosulfate  complexes  in  subsequent  washing,   (b)  how  long 
the  photographic  material  should  be  fixed,  and  (c)  when  the  baths 
should  be  discarded. 

(a)  Choice  of  Baths. — It  has  been  shown  that  the  use  of  single 
fixing  baths  having  pH  values*  lower  than  4.9  retards,  to  a  con- 
siderable degree,  the  removal  of  residual  hypo  and  silver  complexes 
during  subsequent  washing. 

On  the  other  hand,  when  the  pH  of  a  fixing  bath  is  above  the  iso- 
electric  point  of  gelatin  (pH  =  4.9),  no  silver  is  retained  by  the 
processed  film  after  washing,  irrespective  of  the  composition  of  the 
fixing  bath,  and  the  hypo  is  removed  more  rapidly  during  washing 
provided  fixation  is  complete.  It  is  desirable,  therefore,  to  employ, 

*  The  />H  of  fixing  baths  may  be  determined  either  with  glass  electrode  pH 
meters,  appropriate  indicator  solutions,  or  indicator  test  papers  which  may  be 
obtained  from  chemical  apparatus  supply  houses. 


July,  1943]          REMOVAL  OF  HYPO  AND  SILVER  SALTS  53 

whenever  possible,  fixing  baths  at  pH  values  in  the  range  5.0  to  5.5. 
A  consideration  of  the  fundamental  properties  of  fixing  baths  showed 
that  potassium  alum  fixing  baths  containing  boric  acid  or  a  salt  of 
the  acid  such  as  Kodak  F-5,  F-6,  F-10,  and  F-25  could  be  adjusted 
to  />H  values  in  the  range  5.0  to  5.5  without  changing  the  tendency 
to  scum,  the  sludge  life,  the  sulfurization  life,  or  the  degree  of  harden- 
ing. However,  certain  conditions  must  be  fulfilled  before  their 
use  at  these  pH  values  is  practical,  namely : 

(1)  An  acetic  acid  rinse  bath  must  be  used  following  development 
(a)  to  dissolve  calcium  sulfite  scum  from  the  film,  particularly  when 
low  pH  developers  have  been  used,  and  (b)  to  prevent  the  pH  of  the 
fixing  bath  from  increasing  to  a  value  at  which  sludging  and  a  lower 
degree  of  hardening  may  occur.     Potassium  alum-boric  acid  baths 
are  sufficiently  buffered  to  neutralize  the  acetic  acid  introduced 
into  the  bath. 

(2)  It  may  be  necessary  to  use  a  quick  rinse  following  fixation  to 
avoid  the  formation  of  sludge  in  the  wash  water.     This  precipitation 
is  usually  evident  only  during  intermittent  processing  and  may  be 
overcome  by  increased  water  flow  and  the  use  of  the  smallest  possible 
tank.     Squeegees    used   following    the   fixing    procedure    are    very 
helpful. 

Of  the  four  baths  considered,  the  F-6  bath  approaches  this  desirable 
pH  range  as  can  be  seen  from  the  following  initial  pH  values : 

F-5  — />H  =  4.1 
F-10—pU  =  4.6 
F-25—p?L  =  4.2 
F-6  — />H  =  4.9 

The  pH  of  the  F-6  bath  is  at  the  isoelectric  point  of  gelatin  and 
when  this  bath  is  used  only  a  minute  trace  of  silver  is  retained  while 
hypo  is  very  rapidly  removed  during  washing.  F-6,  therefore,  is 
invaluable  in  the  removal  of  silver  and  hypo  when  used  either  as  a 
single  bath  or  as  a  second  bath  in  a  two-  or  three-bath  combination. 
As  a  result  of  the  gradual  addition  of  developer  to  a  fixing  bath 
during  use,  the  pU.  value  increases  so  that,  even  in  the  case  of  the 
F-5,  F-10,  and  F-25  baths  (when  used  with  normally  alkaline  de- 
velopers and  without  an  acid  rinse  bath  or  only  a  short  water  rinse), 
a  point  is  soon  reached  when  they  are  as  satisfactory  as  F-6  from  a 
hypo  and  silver  retention  standpoint.  Beyond  this  point  the  harden- 
ing properties  continue  to  diminish  so  that  it  is  desirable  to  maintain 
the  pH  at  this  value  (about  5,0)  by  replenishment  with  acid. 


54  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 

Although  chrome  alum  fixing  baths  and  hardening  baths  also 
have  advantages  with  respect  to  the  removal  of  hypo  and  silver, 
the  F-6  bath  is  almost  as  effective  in  this  connection  and  has  less 
tendency  to  scum  and  sludge  while  it  does  not  lose  its  hardening 
properties  with  age. 

With  this  important  general  recommendation  in  mind,  recom- 
mendations of  other  fixing  baths  and  fixing  bath  combinations  are 
given  below  for  (1)  continuous  recirculating  systems,  and  (2)  non- 
circulating  systems. 

(1)  Continuous  Recirculating  Systems. — The  use  of  a  single  fixing 
bath,  rather  than  two,  in  continuous  recirculating  systems  such  as 
are  used  in  many  motion  picture  processing  laboratories  is  entirely 
practical  because  the  hardening  properties  and  the  acidity  (pH) 
are  maintained  by  replenishment,  while  the  silver  content  is  kept  at  a 
minimum  (approximately  1.0  gram  per  liter)  by  continuous  electro- 
lytic or  sulfide  recovery  methods.  The  increasing  iodide  content 
of  these  baths,  especially  when  using  high-speed  negative  materials, 
does  not  seriously  affect  the  retention  of  residual  silver  by  the  film. 
The  iodide  content  usually  is  such  that  it  does  not  alter  the  fixing 
time  appreciably.  Several  different  fixing  baths  are  suitable  for  use 
in  these  systems,  namely: 

(A)  A  chrome  alum  bath  similar  to  Kodak  F-23  is  the  most  favor- 
able because  hypo  is  more  readily  removed  after  fixation  in  a  chrome 
alum  bath  than  with  potassium  alum  baths  and  no  supplementary 
treatments  are  necessary.  The  successful  use  of  these  chrome  alum 
baths  is  possible,  however,  only  by  careful  adherence  to  correct 
procedure  as  follows : 

The  baths  should  be  revived  periodically  to  maintain  the  chrome 
alum  concentration  while  the  pH  should  be  held  between  values  of 
3.5  and  4.0.  When  used  intermittently,  chrome  alum  baths  should 
be  replenished  immediately  after  use  to  prevent  sludging. 

Chrome  alum  baths  tend  to  lose  their  hardening  properties  with 
age  even  without  use,  while  an  excessive  amount  of  alkali  carried 
over  from  the  developer  will  tend  to  produce  a  greenish  scum  of 
chromium  hydroxide  on  the  film  or  a  sludge  in  the  bath.10  These 
sludging  or  scumming  difficulties  may  be  prevented  by  (/)  the  use 
of  squeegees  between  developer  and  fixing  bath,  (//)  by  adequate 
replenishment,  and  (///)  by  maintaining  the  pH  of  the  baths  con- 
stant by  the  addition  of  sulfuric  acid.  Suitable  methods  of  main- 
taining the  pH  of  chrome  alum  baths  have  been  described  in  the 


July,  1943  ]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  55 

article  "New  Stop  Baths  and  Fixing  Bath  Formulas  and  Methods 
for  Their  Revival"  (J.  Soc.  Mot.  Pict.  Eng.,  XXXVIII  (April,  1942), 
p.  353. 

(B)  A  potassium  alum  bath  of  the  type  of  F-5  or  F-6  may  be  used. 
F-5  a.t  p*K  =  4.1  requires  a  subsequent  treatment  of  the  film  for  at 
least  3  minutes  in  an  0.03  per  cent  ammonia  solution  near  the  end 
of  the  washing  operation  in  order  to  insure  complete  hypo  removal. 
However,  when  F-6  at  pH  =  4.9  or  F-5  modified  to  a  pH  of  5.0  to 
5.5  is  used,  the  ammonia  treatment  is  not  necessary. 

With  some  potassium  alum  baths,  particularly  F-6,  the  alum  of  the 
fixing  bath  carried  into  the  wash  water  tends  to  hydrolyze,  resulting 
in  sludge  formation.  This  may  be  prevented  by  using  either 
a  spray  washer  or  a  narrow  tank  (to  insure  rapid  removal  of  water) 
just  prior  to  the  passage  of  the  film  into  the  regular  washing  system. 

(C)  A  non-hardening  bath  containing  sulfite  and  bisulfite  (pH  = 
5.6)  may  be  used,  followed  by  washing,  and  then  hardening  in  an 
alkaline  formaldehyde  solution,*  and  washing  provided  the  processing 
temperature  is  maintained  at  68 °F  or  lower  in  order  to  prevent  ex- 
cessive swelling  in  the  baths. 

(2)  Non-  Circulating  Systems  (No  Continuous  Silver  Recovery)  ^ 
• — When  a  single  fixing  bath  is  used  at  a  pH  below  5.0  there  is  an 
accumulation  of  silver  on  exhaustion  and,  in  order  to  be  sure  that 
no  silver  will  remain  in  the  final  product  after  fixation  in  a  partially 
used  bath,  it  is  imperative  to  employ  at  least  two  separate  fixing 
baths  in  succession.  By  this  means  silver  thiosulfates  not  removable 
by  washing  are  taken  out  of  the  film  and  in  addition  the  time  of 
fixation  may  be  reduced  (see  below,  "Time  of  Fixation").  Although 
many  combinations  of  fixing  baths  are  possible,  the  following  are 
suggested : 

(a)  Use   of   two   bisulfite-sulfite   non-hardening   fixing   baths   in 
succession  such  as  Kodak  F-24,  followed  by  washing  and  then  harden- 
ing in  the  above  formalin  solution.     The  processing  temperature 
must  be  maintained  at  68°F  or  lower  to  prevent  excessive  swelling. 

(b)  Use  of  two  potassium  alum  hardening  fixing  baths  similar 
to  Kodak  F-6  at  £H  =  4.9,  followed  by  thorough  washing. 

(c)  Use  of  two  potassium  alum  hardening  fixing  baths  similar 
to  Kodak  F-5  at  pH  =  4.1,  followed  by  thorough  washing.     The 

*  10.0  cc  of  40%  formalin  per  liter  plus  5  grams  of  sodium  carbonate. 


56  CRABTREE,  EATON,  AND  MUEHLER        [j.  S.  M.  P.  E. 

film  is  then  immersed  in  an  0.03  per  cent  ammonia  solution  for  3  to 
5  minutes  and  then  washed  for  5  to  10  minutes. 

(d)  Use  of  a  potassium  alum-boric  acid  bath,  similar  to  Kodak 
F-5,  F-6,  or  F-25,  as  the  first  bath,  followed  by  the  first  bath  with 
the  alum  omitted.     When  the  second  bath  is  transferred  to  the  first 
tank  for  use  as  the  first  bath,  as  described  below,  it  is  necessary  to 
add  hardener.     Besides  removing  silver  thiosulfate,  the  non-harden- 
ing second  bath  causes  more  rapid  removal  of  hypo  and  prevents 
the  possible  formation  of  alumina  sludge  in  the  wash  water. 

(e)  High-temperature  processing  demands  the  use  of  chrome  alum 
baths   which   may   be   employed   in   the   following   combinations: 
a  chrome  alum  hardening  bath  (SB-4)  followed  by  a  non-hardening 
fixing  bath  (F-24),  or  two  chrome  alum  fixing  baths  (F-23). 

To  insure  the  complete  removal  of  residual  silver,  the  non-harden- 
ing bath  used  in  (a)  should  be  discarded  when  it  is  half  exhausted 
with  respect  to  silver  content,  otherwise  two  fixing  baths  should  be 
used  in  combination  with  the  chrome  alum  hardening  bath.  The 
half -exhaustion  point  is  determined  by  the  method  described  on  p.  58. 

(b)  Time  of  Fixation:  (1)  Single  Bath  ''Time  of  Fixation." — When 
the  pH  of  a  fixing  bath  is  greater  than  4.9,  silver  is  not  retained 
by  the  film  and  the  usually  recommended  time  of  fixing  of  twice 
the  "time  to  clear"  is  satisfactory  as  shown  in  Fig.  7.  However, 
when  the  pH  is  maintained  below  4.9  it  has  been  shown  that  the 
use  of  a  single  bath  is  not  practical  because  considerable  quantities 
of  silver  are  retained  by  the  film.  Chrome  alum  fixing  baths  cannot 
be  used  above  pH  =  3.8  to  4.0  because  of  sludging  and  loss  of  harden- 
ing properties.  Thus,  with  pH  maintained  below  4.9  it  is  necessary 
to  use  at  least  two  fixing  baths  in  order  to  remove  completely  the 
silver  by  washing. 

(2)  Time  of  Fixation  with  Two  Fixing  Baths. — Apart  from  being 
impractical,  the  long  times  of  fixation  required  in  an  exhausted 
single  bath  with  £H  below  4.9  caused  increased  retention  of  silver 
thiosulfate  complexes  by  the  film.  A  second  fixing  bath  removes 
the  residual  complexes  retained  from  the  first  bath  and  permits  a 
shorter  time  of  fixing  in  the  first  bath.  The  times  given  below  are 
based  upon  exhausted  first  baths  and  are  not  variable  if  the  complete 
removal  of  silver  is  desired. 

For  the  present-day  high-speed  negative  materials  a  minimum 
time  of  10  minutes  (approximately  twice  the  "time  to  clear"  in  an 
exhausted  bath)  is  recommended  in  the  first  bath  and  a  minimum 


July,  1943]          REMOVAL  OF  HYPO  AND  SILVER  SALTS  57 

time  of  3  minutes  in  the  second  bath  at  68°F.  Minimum  times  of 
5  and  3  minutes,  respectively,  are  suggested  for  positive  type  emul- 
sions. These  times  were  arrived  at  from  a  consideration  of  the 
minimum  time  to  obtain  (a)  complete  fixation,  and  (b)  adequate 
hardening. 

Shorter  times  of  fixation  than  those  given  produce  a  low  degree  of 
hardening  with  the  alum  fixing  baths  and  permit  the  accumulation 
of  too  much  silver  in  the  second  bath,  thereby  defeating  the  purpose 
of  the  second  bath.  Longer  times  of  fixation  than  20  minutes, 
especially  in  the  first  bath,  permit  the  retention  of  greater  quantities 
of  silver  and  hypo.  With  baths  of  low  pH,  if  the  total  fixing  time 
exceeds  20  minutes,  reduction  of  the  silver  image  may  occur.21 

(c)  When  to  Discard  the  Fixing  Bath. — Assuming  that  the  pH  is 
maintained  and  that  there  is  no  sludging  or  sulfurization,  the  fixing 
properties  cease  to  be  satisfactory  when  the  concentration  of  silver 
in  the  bath  exceeds  a  definite  concentration  because  silver  thiosulf ate 
complexes  are  retained  by  the  film.  These  critical  concentrations 
of  silver  are  indicated  in  Table  X  and  may  be  determined  with  the 
Argentometer9  of  Weyerts  and  Hickman.  The  ''Kodak  Testing 
Outfit  for  Fixing  Baths"*  has  been  adjusted  to  indicate  the  maximum 
practical  degree  of  exhaustion  of  a  film  fixing  bath  which  corresponds 
to  a  concentration  of  approximately  6.0  grams  of  silver  per  liter. 

The  Kodak  Testing  Outfit  is  particularly  useful  when  two  fixing 
baths  are  used.  When  a  positive  silver  test  is  obtained  with  the 
first  bath,  it  should  be  discarded.  The  second  bath  is  then  trans- 
ferred to  the  first  tank  or  tray  to  be  used  as  the  first  fixing  bath  and  a 
fresh  solution  used  in  the  second  tank. 

In  cases  of  ordinary  processing  when  archival  storage  is  not  being 
considered,  the  preferred  fixing  procedure  is  to  use  two  fixing  baths, 
but  if  only  a  single  bath  is  used,  it  should  be  discarded  when  the 
silver  concentration  increases  to  6.0  grams  per  liter  to  avoid  possible 
changes  in  the  film  which  might  occur  in  a  very  short  time  of  keeping 
with  quantities  of  silver  greater  than  this. 

In  practice,  the  £H  of  a  single  bath  usually  increases  to  a  degree 
depending  upon  the  developer  carry-over,  but,  if  the  pH  exceeds 
4.9,  no  silver  is  retained  by  the  film.  However,  the  clearing  time 


*  To  determine  the  exhaustion  life  of  the  first  bath,  add  10  drops  of  the  fixing 
bath  to  5  drops  of  the  test  solution  B  (from  the  Kodak  Testing  Outfit).  An  im- 
mediate heavy  yellow  precipitate  indicates  that  the  bath  is  exhausted. 


58  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  P.  E. 

is  usually  at  the  practical  limit  when  the  silver  content  is  6.0  grams 
per  liter  and  the  bath  should  then  be  discarded. 

In  the  case  of  high-temperature  processing  using  a  chrome  alum 
hardening  bath  and  a  non-hardening  fixing  bath,  the  fixing  bath 
should  be  discarded  when  half  exhausted.* 

(3)  The  Washing  Procedure. — The  absolute  time  required  to 
wash  a  given  film  emulsion  is  largely  dependent  upon  the  washing 
equipment  and  conditions  used.  The  more  effective  the  washing 
technique,  the  shorter  the  time  of  washing  required  to  remove  com- 
pletely the  hypo  and  silver. 

Maximum  and  efficient  removal  of  hypo  and  silver  can  be  insured 
by  observance  of  the  following  precautions : 

(a)  Maintenance  of  an  Adequate  Rate  of  Renewal  of  Water  at  the 
Film  Surface. — In  most  cases  neither  the  cascade  nor  the  individual 
tank  systems  using  large  tanks  produces  sufficient  agitation  or  re- 
newal of  fresh  water  at  the  film  surface  to  insure  the  maximum  rate 
of  washing  unless  a  large  number  of  stages  are  used. 

More  rapid  renewal  at  the  film  surface  can  be  insured  either  by 
mechanical  or  air  agitation  or  by  spraying  the  water  onto  the  film 
surface  by  a  suitable  arrangement  of  jets.  It  is  preferable  that  the 
film  be  entirely  submerged  but,  if  this  is  not  practicable,  it  is  very 
important  to  insure  a  uniform  flow  of  water  at  the  film  surface  by 
staggering  the  nozzles  and  to  take  precautions  that  sprockets,  shafts, 
chains,  idlers,  and  other  mechanical  parts  are  adequately  sprayed. 

In  order  to  insure  maximum  efficiency  in  washing,  the  volume  of 
the  wash  tank  for  a  given  flow  of  water  should  be  as  small  as  possible 
so  that  the  turn-over  of  the  water  is  a  maximum.  With  average 
conditions  of  washing  when  using  a  potassium  alum  fixing  bath 
(pH  less  than  4.9),  approximately  one  hour  is  required  to  wash  out 
completely  the  hypo  from  the  thicker  high-speed  negative  emulsions 
such  as  Super- JO"  Negative  Film,  Type  1232.  It  is  apparent, 
therefore,  that  satisfactory  washing  can  not  be  attained  with  in- 
efficient systems  with  a  washing  time  of  only  10  to  15  minutes. 

(b)  Adjustment  of  the  pH  of  Wash  Water.— The  pH  value  of  the 
wash  water  may  be  adjusted  by  the  addition  of  ammonia  at  a  rate 
sufficient  to  maintain  the  />H  between  values  of  9.0  and  10.0.     This 
may  be  accomplished  by  (1)  automatic  pH  control  apparatus  now 


*  Add  5  drops  of  test  solution  B  to  5  drops  of  water,  then  add  10  drops  of 
fixing  bath.     A  heavy  yellow  precipitate  indicates  that  the  bath  is  half  exhausted., 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  59 

commercially  available,  and  (2)  addition  of  ammonia  water  at  a 
suitable  rate  by  means  of  a  constant-level  device  and  a  calibrated 
orifice. 

The  film  should  be  rinsed  before  entering  the  tank  in  which  the 
pH  has  been  adjusted  with  ammonia;  otherwise,  when  using  a 
potassium  alum  bath  a  sludge  of  alumina  would  be  produced.  The 
water  in  the  remaining  tanks  then  washes  the  film  free  of  hypo  and 
ammonia.  Ammonia  in  all  the  tanks  has  no  advantage  over  its 
presence  in  one  or  two  tanks.  It  is  obvious  that  the  use  of  several 
narrow  tanks  is  to  be  preferred  to  only  a  few  larger  tanks.  The 
use  of  squeegees  will,  of  course,  greatly  minimize  the  quantity  of  hypo 
carried  into  the  rinse  and  wash  waters. 

(c)  Control  of  Temperature  of  Wash  Water. — The  temperature 
of  the  wash  water  should  not  be  too  low,  the  most  useful  and  practical 
range  being  60°  to  70°F. 

(4)  Fixing  and  Washing  Paper  Prints.— It  is  obvious  that 
certain  steps  must  be  taken  to  improve  the  commercial  washing  of 
photographic  prints  in  order  to  produce  prints  which  do  not  contain 
more  hypo  than  the  quantities  previously  indicated.  In  order  to  im- 
prove the  washing,  the  following  relatively  simple  operations  should 
be  adopted:  (1)  Raise  the  temperature  of  the  wash  water,  (2)  use 
adequate  mechanical  agitation,  (3)  prolong  the  washing  time,  and 
(4)  employ  the  hypo  eliminator2  if  lower  quantities  of  hypo  are  de- 
sired. 

The  removal  of  hypo  and  silver  from  film  by  washing  was  greatly 
improved  by  (a)  adjusting  the  pH  of  the  fixing  bath  to  a  value  in 
the  range  5.0  to  5.5,  (b)  bathing  in  0.03  per  cent  ammonia  solution, 
(c)  using  a  chrome  alum  fixing  bath  or  the  F-6  potassium  alum  fixing 
bath,  and  (d)  using  a  two-fixing-bath  combination  in  which  the 
second  bath  was  non-hardening  or  at  a  />H  value  higher  than  4.9. 

However,  with  paper  prints  the  above  procedures  assisted  the 
removal  of  hypo  by  washing  only  to  a  small  degree  and  only  during 
the  first  few  minutes  of  washing.  Of  these  treatments  the  com- 
bination of  two  fixing  baths  was  the  only  one  which  assisted  in  the 
removal  of  silver. 

Recommended  potassium  alum  fixing  baths  for  use  with  prints 
are  Kodak  F-l,  F-5,  and  F-6.  Prints  should  be  fixed  for  a  minimum 
time  of  5  minutes  to  insure  thorough  fixation  in  exhausted  baths. 
Longer  times  of  fixation  up  to  15  to  20  minutes  may  be  used  without 
affecting  the  silver  image,  but  under  these  conditions  greater  quan- 


60  CRABTREE,  EATON,  AND  MUEHLER         [j.  s.  M.  P.  E. 

titles  of  hypo  and  silver  are  retained.  When  using  more  than  one 
fixing  bath  it  is  desirable  to  fix  about  5  minutes  in  the  first  bath  and 
from  3  to  5  minutes  in  subsequent  baths.  It  is  never  desirable  to 


FIXED  IN  BATH  NO.) 


MAXIMUM   CONCENTRATION 

OF  SILVER 
BATH  NO.  I 


32  **  9*  iS2  200 

8XIOINCH  PRINTS  PER  GALLON 


FIXED  IN  BATH  NO.i  FOLLOWED  BY  BATH  NO. a 


BATH  NO  2 
O.3  q 


8  32  64  96  152  200 

8XIO-INCH  PRINTS  PER  GALLON 


F1XEP  IN  BATH  NO.*  FOLLOWED  BY  BATH  NO.  3 


. 


BATH  NO. 3 
O.iOqm*/  LITER 


*2  44  96  182  ZOO 

8XIO-INCH  PRINTS  PER  GALLON 


FIG.  14.  Illustrating  the  relative  quantity  of  residual  silver  in 
prints  when  fixed  in  multiple  baths.  After  fixing  and  washing,  the 
prints  were  stored  at  110°F  when  the  silver  thiosulfates  decomposed 
to  yellow  silver  sulfide.  The  quantity  of  silver  sulfide  stain  is 
therefore  an  indication  of  the  probable  appearance  of  the  highlights 
of  the  prints  on  prolonged  storage.  Note  that  the  exhaustion  life 
of  a  single  fixing  bath  is  not  greater  than  twenty-five  8  X  10-inch 
prints  per  gallon,  but  with  three  fixing  baths  the  life  is  at  least  one 
hundred  prints  per  gallon. 

allow  prints  to  soak  for  excessive  times  (30  minutes  or  upward)  in 
the  fixing  bath  because  this  tends  to  retard  easy  removal  of  hypo  by 
washing  and  to  reduce  the  image. 

The  intended  use  of  the  prints  largely  governs  the  method  of 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  61 

fixing  to  be  employed.  In  order  to  obtain  the  most  permanent 
prints  possible,  for  archival  purposes,  it  is  imperative  that  at  least 
two  and  preferably  three  fixing  baths  be  used,  preferably  with  a 
rinse  between  baths.  The  baths  should  be  used  until  the  first  bath 
is  exhausted  as  judged  by  the  "Kodak  Testing  Outfit  for  Acid  Stop 
Baths  and  Fixing  Baths."*  Then  the  second  and  third  baths  are 
used  as  the  first  and  second  baths,  and  the  cycle  is  repeated. 

Fig.  14  illustrates  the  relative  silver  sulfide  stain  produced  by  de- 
composition of  the  retained  silver  thiosulfates  in  prints  fixed  in  the 
three  baths  during  the  processing  of  sufficient  8  X  10-inch  prints  to 
give  a  positive  silver  test  in  the  first  bath  with  the  Kodak  Test  Kit. 
It  is  seen  that  a  second  fixing  bath  will  permit  the  fixation  of  about 
thirty  8  X  10-inch  prints  per  gallon  which  contain  no  silver,  while 
the  use  of  a  third  bath  will  permit  the  fixation  of  about  one  hundred 
8  X  10-inch  prints  per  gallon.  The  baths  were  exhausted  to  two 
hundred  8  X  10-inch  prints  per  gallon  with  samples  taken  out  for 
test  as  indicated.  The  silver  content  of  the  baths  after  this  number 
of  prints  was  processed  is  indicated.  These  values  were  determined 
with  the  Argentometer  described  by  Weyerts  and  Hickman.9 

Following  thorough  fixation  in  at  least  two  successive  fixing  baths, 
the  prints  should  be  washed,  treated  in  the  hydrogen  peroxide-am- 
monia hypo  eliminator,2  washed,  and  further  protected  against 
atmospheric  conditions  as  recommended  in  the  paper  "The  Elimina- 
tion of  Hypo  from  Photographic  Images."2  The  use  of  at  least  two 
and  preferably  three  fixing  baths  previous  to  the  use  of  the  eliminator 
is  imperative  since  the  eliminator  does  not  remove  silver  thiosulfates. 
In  the  absence  of  thorough  fixation,  early  decomposition  of  the 
residual  silver  complexes  to  silver  sulfide  may  occur  causing  staining 
of  the  highlights  of  the  print. 

When  a  single  fixing  bath  is  used  until  exhausted  as  indicated 
by  the  Kodak  Testing  Outfit,  it  contains  about  1.2  to  1.5  grams  of 
silver  per  liter.  Prints  fixed  in  this  solution  will  keep  for  a  short 
time  only,  especially  under  adverse  storage  conditions.  The  maxi- 
mum concentration  of  silver  in  a  fixing  bath  considered  to  be  safe 
for  commercial  purposes  is  approximately  0.30  gram  per  liter  which 


*  To  determine  the  exhaustion  life  of  the  first  bath,  add  5  drops  of  test  solution 
B  to  5  drops  of  water  and  then  add  10  drops  of  the  fixing  bath.  The  bath  is  ex- 
hausted when  a  permanent  heavy  yellow  precipitate  forms.  This  test  is  designed 
to  measure  the  much  lower  critical  concentration  of  silver  in  paper  fixing  baths. 


62  CRABTREE,  EATON,  AND  MUEHLER         [J.  S.  M.  p.  E. 

means  that  only  about  thirty  8  X  10-inch  prints  per  gallon  should 
be  fixed  in  a  single  bath. 

It  is  therefore  considered  necessary,  as  well  as  more  economical 
and  practical,  to  use  two  fixing  baths  in  commercial  processing. 
By  this  means  the  first  bath  can  be  exhausted,  before  being  dis- 
carded, with  one  hundred  fifty  8  X  10-inch  prints  per  gallon  of  fixing 
bath.  This  exhausted  bath  may  then  be  replaced  by  a  fresh  bath  and 
when  this  bath  is  exhausted  with  one  hundred  fifty  8  X  10's  per 
gallon,  the  second  bath  may  be  used  as  the  first  bath.  An  alternative 
is  to  exhaust  the  first  bath  which  is  then  replaced  by  the  second  bath 
and  a  fresh  second  bath  employed.  The  exhausted  bath  should 
contain  about  1.2  to  1.5  grams  per  liter  of  silver  and  give  a  positive 
test  with  the  Kodak  Testing  Outfit. 

A  further  saving  in  time,  because  of  less  handling,  will  result 
from  the  use  of  three  fixing  baths,  in  which  case  four  fresh  first 
baths  may  be  exhausted  before  it  is  necessary  to  move  the  second  and 
third  baths  into  the  first  and  second  positions,  after  which  three  more 
fresh  first  baths  may  be  used,  and  so  on.  This  method  is  not  satis- 
factory for  the  complete  removal  of  residual  silver,  but  only  when 
0.30  gram  of  silver  per  liter  in  the  fixing  bath  can  be  tolerated. 

The  use  of  multiple  fixing  baths  may  be  simplified  by  the  adoption 
of  a  continuous  countercurrent  flow  of  the  fixing  bath  through  a 
series  of  at  least  two  tanks.  This  arrangement  would  eliminate  the 
necessity  of  (a)  moving  the  tanks  from  one  position  to  another, 
(&)  transferring  the  baths  from  one  tank  to  another,  or  (c)  replenish- 
ing the  bath  in  a  single  tank  by  flowing  in  fresh  solution  at  a  con- 
stant rate.  A  countercurrent  flow  system  would  also  reduce  the 
loss  of  silver  usually  incurred  by  the  carry-over  of  partially  ex- 
hausted fixing  bath  into  the  wash  water  since  the  silver  content  of 
the  last  fixing  bath  would  be  at  a  minimum. 

It  has  been  suggested  that  a  fewer  number  of  fixing  baths  contain- 
ing much  greater  quantities  of  hypo  (e.  g.,  60  per  cent)  could  be 
used.  Tests  made  in  this  connection  did  not  show  any  practical 
advantages  in  the  use  of  such  baths. 

To  Summarize. — The  above  recommendations  insure  as  well 
as  is  known  the  absence  of  silver  thiosulfate  and  free  hypo  in  the 
finished  negative  or  print  and,  although  in  most  cases,  if  the  hypo 
and  silver  contents  are  reduced  to  the  permissible  values  suggested 
in  Tables  IX  and  X,  satisfactory  permanency  can  be  expected,  it 
is  desirable  to  follow  the  procedure  for  complete  elimination  in 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  63 

order  to  take  care  of  possible  inefficiencies  in  either  the  fixation  or 
washing  procedures  and  of  possible  abnormal  conditions  of  storage. 

Although  emphasis  has  been  placed  on  the  production  of  perma- 
nent films  and  prints  with  respect  to  the  silver  image,  it  is  of  equal 
interest  and  importance  that  the  photographic  base  shall  have 
equal  permanency. 

Experience  has  shown  that  many  high-grade  book  papers  have 
retained  their  original  characteristics  for  several  hundred  years, 
and  aging  tests  made  by  the  Bureau  of  Standards  22- 23  have  indicated 
that  paper  stock  of  the  type  used  in  photographic  paper  is  as  per- 
manent as  the  high-grade  book  papers  tested.  It  is,  therefore, 
reasonable  to  assume  that  the  photographic  paper  base  will  keep,  at 
least,  for  two  or  three  hundred  years. 

In  the  case  of  films  free  of  residual  hypo  and  silver  and  stored 
at  50°F  or  lower  those  with  nitrate  film  base  will  probably  remain 
unchanged  for  at  least  100  years.  It  is  recommended,  however, 
that  films  for  record  purposes  be  made  on  safety  (acetate)  base 
since  accelerated  aging  tests  made  by  the  Bureau  of  Standards1 
have  indicated  a  greater  permanency  for  acetate  as  compared  with 
nitrate  film  base. 

ACKNOWLEDGMENT 

The  authors  are  indebted  to  Mr.  C.  E.  Ives  for  helpful  suggestions 
and  to  Mr.  C.  J.  Kunz  for  assistance  in  the  experimental  work. 

REFERENCES 

1  HILL,  J.  R.,  AND  WEBER,  C.  G.:     "Stability  of  Motion  Picture  Films  as 
Determined  by  Accelerated  Aging,"  Research  Paper  RP950,  National  Bureau  of 
Standards,  December,  1936. 

2  CRABTREE,  J.  I.,  EATON,  G.  T.,  AND  MUEHLER,  L.  E.:     "The  Elimination  of 
Hypo  from  Photographic  Images,"  /.  Soc.  Mot.  Pict.  Eng.,  XXXV  (May,  1940),  p. 
484. 

3  CRABTREE,  J.  I.,  AND  IVES,  C.  E.:     "The  Storage  of  Valuable  Motion  Pic- 
ture Film,"  /.  Soc.  Mot.  Pict.  Eng.,  XV  (September,  1930),  p.  289. 

4  SIEBERT,  VON  OTTO:     "Wann  haben  unsere  Flatten  und  Bilder  geniigend 
gewassert?"     (When  Are  Plates  and  Prints  Sufficiently  Washed?"),  Das  Atelier 
des  Photographen,  4   (1903),  p.  62.     Refers  to  work  of  Gaedicke.     Cf.     Photo 
Woch.,  Feb.  13,  1900. 

6  LUPPO-CRAMER  :  "Zum  auswaschen  der  Fixier-losungen"  ("On  the  Wash- 
ing Out  of  Fixing  Solutions"),  Phot.  Ind.  (1917),  p.  686. 

6  ELSDEN,  A.  V.:  "The  Removal  of  Hypo  by  Washing  with  Water,"  Brit.  /. 
Phot.,  64  (1917),  p.  119. 


64  CRABTREE,  EATON,  AND  MUEHLER         [j.  s.  M.  P.  E. 

7  HICKMAN,  K.  C.  D.,  AND  SPENCER,  D.  A.:     "The  Washing  of  Photographic 
Products— Part  3,"  Phot.  J.,  48  (1924),  p.  539. 

8  CRABTREE,  J.  I.,  AND  Ross,  J.  F. :     "A  Method  of  Testing  for  the  Presence  of 
Sodium  Thiosulfate  in  Motion  Picture  Films,"  /.  Soc.  Mot.  Pict.  Eng.,  XIV 
(April,  1930),  p.  419. 

9  WEYERTS,  W.  J.,  AND  HICKMAN,  K.  C.  D.:     "The  Argentometer — An  Ap- 
paratus for  Testing  for  Silver  in  a  Fixing  Bath,"  J.  Soc.  Mot.  Pict.  Eng.,  XXV 
(October,  1935),  p.  335. 

10  CRABTREE,  J.  I.,  AND  RUSSELL,  H.  D. :     "Some  Properties  of  Chrome  Alum 
Stop  Baths  and  Fixing  Baths,  Part  I,"  J.  Soc.  Mot.  Pict.  Eng.,  XTV  (May,  1930), 
p.  483;  "Part  II,"  J.  Soc.  Mot.  Pict.  Eng.,  XTV  (June,  1930),  p.  667. 

11  RUSSELL,  H.  D.,  AND  CRABTREE,  J.  I.:     "An  Improved  Potassium  Alum 
Fixing  Bath  Containing  Boric  Acid,"  /.  Soc.  Mot.  Pict.  Eng.,  XXI  (August,  1933), 
p.  137. 

12  ALLISON,  D.  K. :     "Accurate  Laboratory  Control — Part  3,  pH  in  Processing," 
Internal .  Phot.,  9  (1937),  p.  35. 

13  SHEPPARD,  S.  E.,  AND  HOUCK,  R.  C. :     "The  Influence  of  pH  on  Washing 
Films  after  Processing,"  /.  Soc.  Mot.  Pict.  Eng.,  XXXI,  (July,  1938),  p.  67. 

14  CRABTREE,  J.  I.,  AND  MATTHEWS,  G.  E.:     "Effect  of  the  Water  Supply 
on  Photographic  Operations,"  Amer.  Phot.,  XXI  (1927),  p.  634. 

"BASSETT,  H.,  AND  LEMON,  J.  T. :     "Sodium  Thiosulfate-Silver  Thiosulfate 
System,"  J.  Chem.  Soc.,  Part  II  (1933),  p.  142. 

16  BAINES,  H.:     "The  Chemistry  of  Fixation,"  Phot.  J.,  69  (1929),  p.  314. 

17  LUPPO-CRAMER:     "Zur  Konstitution  der  Negativsubstanz"  ("On  the  Com- 
position of  the  Negative  Substance  (Image)"),  Phot.  Korr.,  49  (1912),  p.  121. 

18  LUMIERE,  A.,  AND  L.,  AND  SfiYEWETZ,  A.:     "Sur  la  composition  des  images 
photographiques  obtenues  par  developpement  et  fixage  des  impressions  latentes 
du  gelatino-bromoiodure  et  du  gelatino-bromire  d'argent"  ("The  Composition  of 
Photographic  Images  Obtained  by  Development  and  Fixation  of  Gelatin  Silver 
Bromoiodide  and  Silver  Bromide  Latent  Images"),  Bull.  soc.  franc.,  phot.,  3 
(1912),  p.  36. 

19  CRABTREE,  J.  I.,  AND  MUEHLER,  L.  E.:     "Reducing  and  Intensifying  Solu- 
tions for  Motion  Picture  Film,"  /.  Soc.  Mot.  Pict.  Eng.,  XVII  (December,  1931), 
p.  1025. 

20  GARY,  E.,  AND  WHEELER,  A.  H. :     "Quantitative  Tests  for  Residual  Hypo," 
Amer.  Phot.,  XXXVI  (Jan.,  1942),  p.  16. 

21  RUSSELL,  H.  D.,  AND  CRABTREE,  J.  I.:     "The  Reducing  Action  of  Fixing 
Baths  on  the  Silver  Image,"  /.  Soc.  Mot.  Pict.  Eng.,  XVHI  (March,  1932),  p.  371. 

22  RASCH,  R.  H.,  AND  SCRIBNER,  B.  W.:     "Comparison  of  Natural  Aging  of 
Paper  with  Accelerated  Aging  by  Heating,"  Bureau  of  Standards  Journal  of  Re- 
search,   11    (1933),    p.    727. 

23  RASCH,  R.  H.,  SHAW,  M.  B.,  AND  BICKING,  G.  W.:     "Highly  Purified  Wood 
Fibers  as  Paper  Making  Material,"  Bureau  of  Standards  Journal  of  Research,  7 
(1931),  p.  765. 

BIBLIOGRAPHY 

1890     DUNMORE,  E.:     "About  Hypo,"  B.  J.  Phot.,  37  (1890),  p.  327.     Warm 
water  is  preferable  to  cold.     Imperfect  fixation  is  the  most  frequent 


July,  1943]  REMOVAL  OF  HYPO  AND  SILVER  SALTS  65 

cause  of  fading  prints.     Two  fixing  baths  are  recommended  with  an  inter- 
vening rinse. 

1893  GRUNDY,  F.  B.,  AND  HADDON,  A.:  "On  the  Amounts  of  Silver  and  Hypo 
Left  in  Albuminized  Paper  at  Different  Stages  of  Washing,"  B.  J.  Phot., 
40  (1893),  p.  511.  Silver  thiosulfate  complexes  were  not  removed  after 
two  or  nineteen  hours  of  washing.  Claims  that  the  earliest  reference  to 
this  fact  was  by  JOHN  SPILLER,  Phot.  News,  471  (1862),  p.  471. 

1902  LUMIERE,  A.,  AND  L.,  AND  SEYEWETZ,  A.:     "Sur  1'elimination  par  lavage 
a  1'eau  de  1'hyposulfite  de  soude  retinu  par  les  papiers  et  les  plaques  photo- 
graphiques"  ("The  Elimination  of  Hyposulfite  of  Soda  from  Papers  and 
Films  by  Washing  with  Water"),  Bull.  soc.  fran$.  Phot.,  18  (1902),  p.  251; 
cf.  B.  J.  Phot.,  49  (1902),  p.  392.     The  last  traces  of  hypo  were  very 
difficult  to  remove.     Graphs  are  included.     The  vigorous  retention  of 
hypo  was  attributed  to  adsorption  by  the  paper. 

1903  SIEBERT,  VON  OTTO:     "Wann  haben  unsere  Flatten  und  Bilder  geniigend 
gewassert?     ("When  Are  Plates  and  Prints  Sufficiently  Washed?"),  Das 
Atelier  des  Photo graphen,  4  (1903),  p.  62.     Relative  washing  rates  were 
determined  by  testing  the  hypo  in  the  wash  water.     Referred  to  work  of 
Gaedicke  (Photographische  Wochenblatt,  1900)  who  claimed  that  alum  hard- 
ened plates  required  excessive  washing  as  compared  with  non-hardened 
plates. 

1908  LUMIERE,  A.,  AND  L.  ,  AND  SEYEWETZ,  A.:  "Entfernung  des  fixiernatrons 
durch  Waschen  mit  Wasser"  ("Removal  of  Sodium  Thiosulfate  by  Wash- 
ing with  Water"),  Eder's  Jahrbuch,  (1908),  p.  502.  Increased  tempera- 
ture of  the  wash  water  caused  an  increased  rate  of  washing. 

1908  LUPPO-CRAMER:  "Kolloid  Chemie  und  Photographie,"  (1908),  p.  133. 
Silver  thiosulfate  complexes  can  only  be  washed  out  of  films  by  hypo 
solution. 

1910  HAUBERRISSER,  G.:  "Uber  das  Entfernen  von  Fixiernatron  aus  photo- 
graphischen  Schichten  durch  Auswassern  bei  hoherer  Tempera tur" 
("Removal  of  Hypo  from  Photographic  Layers  by  Washing  at  Elevated 
Temperatures"),  Phot.  Rund.,  24  (1910),  p.  91.  An  increase  in  tempera- 
ture of  the  wash  water  from  60°  to  70°  C  produced  a  considerable  increase 
in  the  rate  of  removal  of  the  hypo. 

1912  LUPPO-CRAMER:  "A  Note  on  the  Difference  of  Time  for  the  Removal  of 
Hypo  from  Plates  Fixed  in  Ordinary  and  Acid  Fixing  Baths,"  Brit.  J. 
Phot.,  59  (1912),  p.  638.  An  acid  fixing  bath  '(non-hardening)  washed  out 
much  more  slowly  than  a  plain  fixing  bath. 

1917  ELSDEN,  A.  V.:  "The  Removal  of  Hypo  by  Washing  with  Water,"  Brit.  J. 
Phot.,  64  (1917),  p.  119.  Only  neutral  thiosulfate  was  used  and  no  ac- 
count taken  of  adsorption  of  thiosulfate. 

1917  LUPPO-CRAMER:  "Zum  auswaschen  der  Fixier-losungen"  ("On  the  Wash- 
ing Out  of  Fixing  Solutions"),  Phot.  2nd.  (1917),  p.  686.  An  acid  fixing 
bath  (non-hardening)  washed  out  much  more  slowly  than  a  plain  fixing 
bath. 

1917  WARWICK,  A.  W.:  "Scientific  Washing  of  Negatives  and  Prints,"  Amer. 
Phot.,  XI  (1917),  p.  317.  Negative  materials  should  be  washed  so  that 
the  hypo  content  is  reduced  to  at  least  0.001  mg  per  sq-in  at  which  con- 


66  CRABTREE,  EATON,  AND  MUEHLER         [j.  s.  M.  P.  E. 

centration  there  is  no  effect  on  the  image.  A  mathematical  treatment  of 
washing  is  given. 

1917  "The  Workroom  (Washing),"  Phot.  J.  of  Amer.,  54  (1917),  p.  231.  It  is 
claimed  that  a  number  of  soakings  and  frequent  changes  are  more  ef- 
fective than  the  use  of  running  water  for  the  elimination  of  hypo. 

1923  DECK,  N.  C.:  "The  Permanence  of  Photographic  Prints  as  Tested  by 
Tropical  Climates,"  Aus.  Photo-Review,  30  (1923),  p.  15.  Washing  prints 
is  insufficient  protection  against  fading  when  the  prints  are  improperly 
fixed. 

1923  CHARRIOU,  DEM.  ANDRE:     "Adsorption  de  I'hyposulfite  de  sodium  par  les 
papiers  photographiques"   ("The  Adsorption  of  Sodium  Thiosulfate  by 
Photographic  Papers"),  Compt.  rend.,  177  (1923),  p.  482.     It  is  impossible 
to  remove  all  of  the  hypo  in  paper  by  washing  because  the  last  traces  are 
adsorbed.     The  elimination  is  much  more  rapid  and  complete  when 
washing  the  prints  with  solutions  of  alkali  carbonates  or  phosphates. 

1924  HICKMAN,  K.  C.  D.,  AND  SPENCER,  D.  A. :     "The  Washing  of  Photographic 
Products,  Parts  3,  4,  and  5,"  Phot.  J.,  64,  NS48  (1924),  p.  539.     The 
water  changing  capacity  of  the  apparatus  is  of  much  greater  importance 
than  the  nature  of  the  plates.    Potassium  alum,  when  used  in  a  5  per  cent 
solution  prior  to  fixing,  retards  the  washing  out  of  an  "electrolyte:"     Cf. 
SPENCER,  D.  A.,  Phot.  J.,  53  (1929),  p.  317,  where  this  is  further  discussed 
but  the  electrolyte  not  identified.     However,  when  used  in  Kodak  acid 
fixing  bath  there  was  no  difficulty  in  removing  hypo  or  electrolyte.     (Note: 
The  Kodak  acid  fixing  bath  at  that  time,  containing  alum,  probably  also 
contained  a  hydroxy  acid  which  impaired  the  hardening  properties  and 
did  not  cause  mordanting.) 

1924  LUMIERE,  A.,  AND  L.,  AND  SEYEWETZ,  A. :  "A  propos  du  fixage  des  plaques 
photographiques,  limite  d'emploi  des  bains  fixateurs"  ("The  Limit  of  Use- 
fulness of  Fixing  Baths  for  Photographic  Plates"),  Bull.  soc.  franq.  Phot., 
11  (1924),  p.  66.  Baths  containing  2  per  cent  silver  bromide  will  not 
completely  remove  silver  salts  from  an  emulsion.  See  Photographe,  65 
(March,  1924). 

1924  CLERC,  L.  P.:     "Observations  sur  la  Note  deM.  Charriou  reproduite  au 
Bulletin  date  de  decembre  1923"   ("Observations  on  the  Note  of  Mr. 
Charriou"),  Bull,  soc.  franc,,  phot.,  11  (1924),  p.  84.     Tests  of  Mr.  Charriou 
did  not  take  into  account  the  various  factors  known  to  influence  the  ef- 
ficacy of  washing.     The  errors  due  to  these  omissions  probably  exceed  the 
differences  included  in  removing  hypo  from  prints  treated  with  pure 
water  and  solutions  of  sodium  bicarbonate. 

1925  HICKMAN,  K.  C.  D.,  AND  SPENCER,  D.  A. :     "The  Washing  of  Photographic 
Products— Part  6,  The  Washing  of  Bromide  Prints,"  Phot.  J.,  65,  NS49 
(1925),  p.  443.     The  removal  of  thiosulfate  from  papers  is  not  exponential 
apparently  because  of  retention  by  the  paper  fibers. 

1925  HICKMAN,  K.  C.  D.:  "Washing  Motion  Picture  Film,"  Trans.  Soc.  Mot. 
Pict.  Eng.,  23  (January,  1925),  p.  62.  Hypo  removal  from  motion  pic- 
ture film  was  shown  to  be  an  exponential  process. 

1925    AMOR,  A.  E.:     "Hypo  Elimination,"  Brit.  J.  Phot.,  72  (1925),  p.  18.     Con- 


July,  1943]          REMOVAL  OF  HYPO  AND  SILVER  SALTS  67 

eluded  that  washing  in  running  water  is  more  rapid  and  efficient  than 
washing  by  changes  with  or  without  the  use  of  an  eliminator. 
1926  STRAUSS,  P.:  "Ueber  die  Ausmitzungsgrenze  des  Fixierbades"  ("The 
Limit  of  Usefulness  of  Fixing  Baths"),  Atelier,  33  (1926),  p.  63.  The 
time  of  fixing  should  be  extended  as  long  as  possible  for  "good  bathing  is 
good  washing."  Dilute  potassium  iodide  solution  was  recommended 
for  testing  the  exhaustion  point  of  the  bath. 

1928  CONNER,  E.:     "When  Is  a  Plate  Fixed?"  Bull.  Phot.,  43  (1928),  p.  778. 
A  plate  is  thoroughly  fixed  when  the  milkiness  disappears  and  no  silver 
remains  in  the  gelatin  film  after  washing  thoroughly. 

1929  SPENCER,  D.  A. :     "Rate  of  Washing,"  Phot.  J.,  53  (1929),  p.  317.     Wash- 
ing anomalies  resulting  from  potassium  alum  hardening  are  discussed. 
An  unidentified  but  difficultly  removed  component  was  present  when 
the  film  was  hardened  with  potassium  alum. 

1929  GARRIGA,  R.:  "Limit  of  Use  of  Fixing  Baths,"  El.  prog,  jot.,  10  (1929), 
p.  61.  Recommended  that  10  cc  of  a  4  per  cent  potassium  iodide  be  added 
to  100  cc  of  fixing  bath  to  determine  if  it  is  exhausted. 

1931  MACONOCHIE,  A.  A.:  "The  Why  and  How  of  Washing  Negatives  and 
Prints,"  Brit.  J.  Phot.,  78  (1931),  p.  241.  For  most  efficient  washing, 
rapid  renewal  of  the  water  at  the  film  surface  is  necessary. 

1931  JUDGE,  A.  W.:  "Efficient  Plate  and  Print  Washing,"  Amer.  Phot.,  25 
(1931),  p.  20.  Washing  is  effective  only  after  all  silver  salts  have  been 
removed  in  the  fixation  process. 

1935  WEYDE,  E. :  "On  the  Possibility  of  Improving  the  Permanence  of  Photo- 
graphic Prints,"  Brit.  J.  Phot.,  82  (1935),  p.  376.  See  also  Photo  Woche, 
25  (1935),  p.  474.  A  bath  of  1  per  cent  sodium  carbonate  used  after 
fixing  facilitates  the  removal  of  hypo  by  washing  with  water. 

1937  LAZENBY,  P.:  "Fixing  and  Washing,"  Min.  Camera  World,  I  (1937), 
p.  633.  Acid  hypo  (non-hardening)  is  more  difficult  to  remove  from  paper 
than  plain  hypo. 

1937  "Analecta — Testing  Exhausted  Fixing  Baths,"  Brit.  J.  Phot.,  84  (1937), 
p.  104;    also  Phot.  Rund.,  74  (1937),  p.  33.     Add  3  or  4  drops  of  10  per 
cent  potassium  iodide  to  20  cc  of  fixing  bath.     An  insoluble  yellow  pre- 
cipitate indicates  the  bath  to  be  exhausted. 

1938  SHEPPARD,  S.  E.,  AND  HOUCK,  R.  C.:     "The  Influence  of  pH.  on  Washing 
Films  after  Processing,"  J.  Soc.  Mot.  Pict.  Eng.  XXXI  (July,  1938),  p.  67. 
With  an  acid  fixing  and  hardening  bath  and  washing  at  the  iso-electric 
point  of  gelatin  the  time  required  to  remove  hypo  is  greater  than  at  pH.  =  7 
to  8.     With  a  non-hardening  acid  fixing  bath  there  was  little  difference  in 
the  washing  times. 

1938  SHAW,  W.  B.:  "Toning  by  Used  Hypo,"  Brit.  J.  Phot.,  85  (1938),  p.  159. 
Although  hypo  may  be  readily  washed  out  of  a  gelatin  film  by  water, 
the  silver  thiosulfate  complexes  formed  during  the  fixing  process  can  not  be 
wholly  washed  out  by  water  alone. 

1940  CRABTREE,  J.  I.,  EATON,  G.  T.t  AND  MUEHLER,  L.  E. :  "The  Elimination 
of  Hypo  from  Photographic  Images,"  J.  Phot.  Soc.  of  Amer.,  VI  (1940),  p.  6. 
Kodak  Research  Laboratories  Communication  No.  780.  Under  ideal  con- 
ditions of  water  renewal,  the  two  most  important  factors  which  affect  the 


68  CRABTREE,  EATON,  AND  MUEHLER 

rate  of  washing  are  (7)  the  temperature  of  the  wash  water,  and  (2)  the 
composition  of  the  fixing  bath.  The  rate  of  removal  increased  with  in- 
creased temperature  and  when  non-hardening  fixing  baths  were  used  in- 
stead of  hardening  fixing  baths.  Chrome  alum  hardening  fixing  baths 
increased  the  rate  of  washing  as  compared  with  potassium  alum  baths. 
The  necessity  for  the  elimination  of  hypo  in  prints  to  a  low  limit  is  shown 
and  the  development  of  an  efficient  peroxide-ammonia  eliminator  for 
prints  is  described. 

1941  DURHAM,  H.  E.:  "Hypo  Eliminators,"  Brit.  J.  Phot.,  88  (1941),  p.  135. 
It  is  claimed  that  a  too  rapid  change  of  water  in  the  early  stages  of  wash- 
ing is  likely  to  cause  the  deposition  of  an  insoluble  silver-sodium  thiosul- 
fate  complex. 

1920-1941  "Letters  to  the  Editor,"  Brit.  J.  Phot.,  67-88  (1920-1941).  The 
complex  silver  thiosulfates  were  considered  to  be  the  major  cause  of  the 
impermanence  of  negatives  and  prints.  Invariably  a  second  fixing  bath 
was  considered  essential  to  eliminate  the  complexes.  The  removal  of  the 
last  traces  of  hypo  by  washing  was  not  considered  in  these  discussions. 


EFFECT  OF  HIGH-INTENSITY  ARCS  UPON  35-MM  FILM 

PROJECTION* 

E.  K.  CARVER,  R.  H.  TALBOT,  AND  H.  A.  LOOMIS** 


Summary. — In  the  study  of  the  effects  of  high-temperature  arcs  on  35-mm  motion 
picture  projection,  it  was  noticed  that  the  sharpness  of  the  image  on  the  screen  was 
'  materially  affected  by  changes  in  the  heat  intensity.  This  indicated  that  film  does 
not  always  lie  in  a  flat  plane  in  a  projector  gate  but  takes  different  positions  at  dif- 
ferent lemperatures.  In  order  to  study  this  phenomenon  more  carefully,  a  portion  of 
the  projector  gate  was  cut  away  permitting  high-speed  Cine  Kodak  pictures  (about 
1500  frames /second)  to  be  taken  of  the  film  as  it  passed  by  the  aperture  of  a  projector. 
The  pictures  show  that  most  films  enter  the  gate  in  a  state  of  slight  positive  curl  (curl 
toward  the  emulsion)  and  then  change  to  a  state  of  negative  curl  during  the  instant 
they  remain  exposed  to  the  heat  of  the  arc.  This  change  in  curl  is  due  to  the  expansion 
of  the  emulsion  layer  by  the  heat.  This  effect  is  especially  pronounced  with  the  new 
high-intensity  arcs. 

The  effect  on  the  quality  of  the  screen  image  of  this  change  in  curl  of  the  film  in  the 
gate  was  studied  by  means  of  high-speed  Cine  Kodak  analysis  of  the  screen  image. 
The  pictures  show  that  at  high  heat  intensities  and  with  the  projector  focused  to  give 
the  sharpest  image  on  the  screen,  the  images  are  in  sharp  focus  for  only  a  portion  of 
their  duration  on  the  screen.  Each  screen  image  comes  into  view  out  of  focus  and 
gradually  becomes  sharper  until  just  before  the  pull-down  when  it  reaches  its  maximum 
sharpness.  Such  pictures  are  of  good  screen  quality  if  the  projector  is  focused  care- 
fully. 

Under  certain  conditions,  when  the  film  is  in  a  very  moist  state  and  when  lamps  of 
the  highest  heat  intensity  are  used,  the  screen  images  may  not  all  be  sharp.  Occasion- 
ally a  few  frames  may  be  entirely  out  of  focus.  The  high-speed  analysis  of  the  action 
of  the  film  in  the  gate  shows  that  these  out-of-focus  frames  behave  in  an  abnormal 
manner.  In  these  frames  the  normal  change  in  curl  from  positive  to  negative  in  the 
gate  is  interrupted  by  a  reversal  back  to  positive  curl.  Thus  at  the  end  of  the  pull-down 
cycle  these  frames  lie  in  a  plane  slightly  toward  the  lens  of  the  projector,  whereas  all  of 
the  normal  frames  lie  in  a  plane  slightly  toward  the  lamp  from  the  plane  of  the  gate. 
The  distance  between  these  two  planes  is  greater  than  the  depth  of  focus  of  the  lens  and 
thus  these  abnormal  frames  appear  out  of  focus.  It  is  believed  that  this  sudden  re- 
versal to  positive  curl  is  due  to  a  contraction  of  the  gelatin  due  to  loss  of  moisture. 

We  recommend  that  the  heat  intensity  at  the  aperture,  as  measured  by  a  thermo- 
couple which  we  have  described,  should  not  exceed  1250°F  and  that  films  should  be 
dried  thoroughly. 

*  Presented  at  the  1942  Fall  Meeting  at  New  York,  N.  Y. 
**  Eastman  Kodak  Company,  Rochester,  N.  Y. 

69 


70  CARVER,  TALBOT,  AND  LOOMIS  [J.  S.  M.  P.  E. 

Recent  improvements  in  arc  lamps  and  carbons  which  have 
made  possible  brighter  pictures  on  the  screen  have  brought  forward 
again  the  problem  of  the  effect  of  extreme  heat  on  motion  picture 
film. 

Whereas  in  the  past  a  thermocouple  held  in  the  gate  of  a  projector 
seldom  reached  a  temperature  of  1000°F,  some  of  the  arcs  and  lamps 
now  in  use  may  heat  the  thermocouple  to  as  high  as  1700  °F.  These 
excessively  high  temperatures  are  not  without  effect  upon  the  physical 
state  of  the  film  subjected  to  them  and  consequently  on  the  resulting 
picture  quality.* 

The  purpose  of  this  paper  is  to  illustrate  the  physical  changes 
that  take  place  in  the  film  during  the  brief  time  it  remains  stationary 
in  the  gate  of  the  projector  and  is  subjected  to  these  high  tempera- 
tures, as  well  as  the  effect  that  these  phenomena  have  upon  the 
appearance  of  the  screen  images. 

Shift  of  Focus  with  Changes  in  Arc  Intensity. — Changes  in  the  heat 
intensity  at  the  aperture  were  measured  by  inserting  a  thermocouple 
at  the  center  of  the  aperture  in  the  exact  plane  normally  occupied  by 
the  film.  An  iron -constan tan  thermocouple  terminating  in  a  stain- 
less steel  disk  6  mm  in  diameter  was  employed.  The  temperature 
which  this  thermocouple  will  attain  is  arbitrarily  called  "heat  in- 
tensity." This  manner  of  estimating  heat  intensities  is  admittedly 
empirical,  and  is  influenced  by  the  size  and  color  of  the  disk,  radiation 
therefrom,  etc.,  but  furnishes  quite  reproducible  results. 

It  was  noticed  immediately  that  the  sharpness  of  the  picture 
upon  the  screen  was  influenced  materially  by  the  heat  intensity. 
A  picture  whose  image  was  in  sharp  focus  with  a  heat  intensity  of 
1000°F  could  be  thrown  decidedly  out  of  focus  if  the  heat  intensity 
were  raised  or  lowered  a  few  hundred  degrees.  This  indicated  that 
film  does  not  always  lie  in  the  same  plane  in  the  gate  but  takes 
different  positions  at  different  temperatures.  In  order  to  demon- 
strate this  more  clearly  and  at  the  same  time  obtain  a  measure  of  these 
displacements,  it  was  necessary  to  calibrate  the  projector  lens  system 

*  The  original  title  of  this  paper  was,  "Effect  of  High  Gate  Temperatures  upon 
35-Mm.  Film  Projection,"  The  use  of  the  expression,  "gate  temperatures,"  was 
criticized  severely  (and  correctly)  because  of  the  fact  that  the  gate  itself  does  not 
have  a  high  temperature.  The  gate  is  merely  a  pathway  through  which  the  in- 
tense radiant  heat  travels.  The  thing  of  importance  is  the  intensity  of  this  heat 
flux  and  not  the  temperature  of  the  air  within  the  gate,  which,  of  course,  is 
approximately  room  temperature.  The  new  title,  therefore,  describes  more  ac- 
curately the  effects  to  be  discussed. 


July,  1943] 


EFFECT  OF  HIGH-INTENSITY  ARCS 


71 


so  that  axial  displacement  of  the  center  of  the  film  in  the  aperture 
could  be  followed  by  noting  the  distance  the  lens  must  be  moved 
from  its  normal  position  to  keep  the  image  in  sharp  focus  upon  the 
screen. 

Study  of  Film  Movement  in  Aperture  by  Focusing  Method. — The 
lens  system  was  calibrated  by  attaching  an  indicator  to  the  system 
as  shown  in  Fig.  1.  The  lower  part  of  the  indicator  hand  is  attached 


FIG.  1.     Focus  indicator  on  E-7  projector. 

directly  to  the  lens  barrel,  then  to  a  fixed  fulcrum  which  magnifies 
the  lens  displacement  at  the  tip  of  the  pointer  so  that  lens  move- 
ments of  0.01  inch  are  read  plainly  and  movements  of  the  order  of 
0.0025  inch  can  be  estimated.  ' 

The  focus  indicator  was  calibrated  in  the  following  manner:  A 
strip  of  film  was  held  in  a  perfectly  flat  position  in  the  gate  by  means 
of  a  piece  of  steel  35  mm  in  width.  A  small  hole  drilled  in  the  center 
of  this  metal  strip  allowed  a  portion  of  the  test  image  to  be  projected 
upon  the  screen.  Since  the  film  was  not  in  motion  a  faint  source  of 
light  was  used  at  a  considerable  distance  from  the  film  in  order  to 


72 


CARVER,  TALBOT,  AND  LOOMIS 


[J.  S.  M.  P.  E. 


eliminate  any  heat  effect.     Thus  the  lens  setting  for  best  visual  focus 
for  perfectly  flat  film  in  the  gate  was  established.     This  we  shall  call 
"zero  focus."     In  a  like  manner,  the  lens  setting  for  film  that  has- 
been  displaced  a  known  amount  was  obtained  by  mounting  the  film 
on  metal  shims  of  known  thickness  and  placing  the  shims  against  the 


FIG.  2.     E-7  gate  cut  away  for  aperture 
pictures. 

film  trap.  Thus  if  a  shim  0.01  inch  in  thickness  were  used,  the  film 
would  be  moved  axially  toward  the  lens  0.01  inch.  The  best  visual 
focus  was  again  obtained  by  projection  of  the  image  and  the  focus 
indicator  calibrated.  As  is  well  known,  film  that  curls  so  that  the  emul- 
sion side  is  concave  is  referred  to  as  having  "positive  curl,"  and  film 
that  curls  in  the  opposite  direction  is  referred  to  as  having  "negative 
curl."  Since  the  film  in  the  gate  has  its  emulsion  side  toward  the  arc, 


July,  1943] 


EFFECT  OF  HIGH- INTENSITY  ARCS 


73 


and  has  its  edges  pressed  against  the  gate,  it  will  be  seen  that  if  film 
has  positive  curl,  the  image  plane  at  the  center  of  the  film  will  be 
shifted  toward  the  lens  of  the  projector.  The  shift  of  the  lens  in 
order  to  correct  for  this  displacement  will  be  referred  to  as  a  positive 
focus.  In  like  manner,  if  the  film  in  the  gate  of  the  projector  has  a 


FIG.  3.     E-7  gate  with  reference  bar  at- 
tached. 


negative  curl,  the  image  plane  at  the  center  of  the  film  will  be  dis- 
placed in  the  opposite  direction  or  toward  the  lamp.  The  shift  of 
the  lens  to  correct  for  this  displacement  will  be  referred  to  as  a 
negative  focus.  Thus  it  may  be  seen  that  the  effective  position  of  the 
film  in  the  gate,  so  far  as  the  screen  image  is  concerned,  may  be 
arrived  at  during  projection  simply  by  setting  the  lens  at  the  best 


74 


CARVER,  TALBOT,  AND  LOOMIS 


[J.  S.  M.  p.  E. 


visible  focus  and  reading  the  displacement  of  the  lens  in  bundredths 
of  an  inch  on  the  dial. 

It  was  discovered  immediately  that  almost  without  exception  new 
films  projected  at  the  customary  heat  intensity  of  about  850  °F  or 
higher  assumed  a  negative  curl  in  the  aperture.  This  was  viewed 
at  first  as  a  rather  disconcerting  discovery  inasmuch  as  such  films  are 


FIG.  4.     Cut-away  E-7  gate  on  projector. 

almost  always  in  a  state  of  slight  positive  curl.  In  fact,  film  entering 
and  leaving  the  gate  was  observed  to  have  slight  positive  curl,  and 
yet  the  focus  indicator  showed  plainly  that  the  film  in  the  aperture, 
while  the  image  was  being  projected  upon  the  screen,  was  negative 
in  curl  to  the  extent  of,  in  many  cases,  at  least  0.01  inch.  On  the 
other  hand,  it  is  quite  logical  to  assume  that  temperatures  of  this 
magnitude,  even  though  operating  but  for  an  instant,  could  effect 
this  change  in  the  physical  state  of  the  film.  One  has,  in  effect,  a 
situation  analogous  to  a  bimetallic  strip  such  as  is  used  in  many 


July,  1943]  EFFECT  OF  HIGH-INTENSITY  ARCS  75 

thermostats.  This  consists  of  two  bonded  metal  strips,  one  having 
a  greater  coefficient  of  expansion  than  the  other.  When  heated,  the 
strip  is  forced  to  assume  a  curvature  convex  to  the  more  rapidly  ex- 
panding element.  In  our  case,  the  emulsion  layer  and  the  support 
form  the  two  members  of  the  strip.  The  expansion  takes  place  al- 
most wholly  in  the  emulsion  layer  since  the  support  absorbs  practi- 


FIG.  5.     High-speed  Cine  Kodak  focused  on  aperture. 

cally  none  of  the  heat.     Expansion  of  the  emulsion  layer  would  force 
the  strip  of  film  to  be  convex  to  the  emulsion  or  negative  in  curl. 

Study  of  Film  Travel  in  Aperture  by  High-Speed  Camera  Analysis 
"Negative  Drift." — In  order  to  determine  at  what  point  in  the  pull- 
down cycle  the  reversal  of  curl  took  place,  high-speed  motion  pictures 
were  taken  of  the  film  as  it  passed  through  the  aperture.  In  most  of 
this  work,  a  Simplex  E-7  projector  with  a  McAuley  Hy- Candescent 
Lamp  and  New  Super  H.I.  National  carbons  was  used.  However, 


76 


CARVER,  TALBOT,  AND  LOOMIS  [J.  S.  M.  P.  E. 


SHADOW  OF  THE 
PULL-DOWN  BLADE 


16  PICTURES 


SHADOW    OF    THE 

FLICKER    BLADE 

12   FRAMES 


certain  phases  of  the  work  were  repeated  with  other  projectors  and 

other  lamps  and  the  same  results  were  obtained. 

It  was  necessary  to  cut  away  a 
portion  of  the  E-7  gate,  as  shown  in 
Fig.  2,  in  order  to  obtain  the  pic- 
tures of  the  film  as  it  passed  by 
the  aperture.  A  reference  bar  was 
attached  to  the  gate  so  that  slight 
movements  of  the  film  in  rela- 
tion to  this  bar  could  be  observed. 
(See  Fig.  3.) 

Fig.  4  shows  this  special  gate  in 
place  on  the  projector  and  Fig.  5 
shows  the  high-speed  Cine  Kodak 
in  position  to  take  the  pictures. 
The  pictures  were  taken  at  an 
angle  of  about  15  degrees  from  the 
plane  of  the  film. 

By  this  means  pictures  have 
been  taken  of  film  in  the  aperture 
of  projectors  at  a  rate  of  about 
1500  frames  per  second.  In  other 
words,  with  film  traveling  through 
the  35-mm  projector  at  the  nor- 
mal rate  of  24  frames  per  sec- 
ond and  with  the  film  remaining 
stationary  in  the  aperture  for  y32 
second,  about  sixty  16-mm  ex- 
posures were  made  between  suc- 
cessive pull-downs.  As  is  known, 
there  are  two  blades  on  the  shut- 
ter of  a  standard  35-mm  projector. 
One  blade  is  to  mask  the  movement 
of  the  film  as  it  comes  into  place 
in  the  aperture,  and  the  purpose 
of  the  other  blade  is  to  interrupt  the 
light  once  during  projection  so  as 
to  keep  the  periods  of  dark  and 

light  on  the  screen  of  more  equal  duration  and  thus  minimize  flicker. 

Therefore,  the  16-mm  high-speed  pictures  have  a  dark  portion  of 


16   PICTURES 


SHADOW  OF  THE 
PULL-DOWN    BLADE 


FIG.  6.  High-speed  pictures  of 
35-mm  film  in  the  aperture.  The 
pictures  represent  the  interval  from 
the  end  of  one  pull-down  to  the 
start  of  the  next  pull-down. 


July,  1943] 


EFFECT  OF  HIGH-INTENSITY  ARCS 


77 


about  12  frames  between  consecutive  pull-downs  of  the  35-mm  film, 
representing  the  blocking-out  of  the  light  by  the  flicker  blade.  A 
typical  sequence  of  pictures  obtained  from  the  end  of  one  pull-down 
to  the  beginning  of  the  next  is  shown  in  Fig.  6. 

When  the  16-mm  pictures  were  projected  the  movement  of  the 
35-mm  film  in  the  aperture  of  the  projector  could  be  clearly  seen. 


FIG.  7.     Enlargement  of  four  frames  from  film  shown  in  Fig.  6. 

(1)  Immediately  after  the  pull-down. 

(2)  Immediately  before  the  flicker  blade. 

(3)  Just  after  the  nicker  blade. 

(4)  Just  prior  to  the  next  pull-down. 

The  pictures  show  that  the  film  comes  into  the  aperture  in  its  nor- 
mal state,  i.  e.,  flat  or  slightly  positive  in  curl;  then  as  the  heat  strikes 
the  film  the  emulsion  layer  expands,  forcing  the  film  into  a  state  of 
negative  curl.  The  expansion  of  the  film  starts  immediately  after 
the  pull-down  and  reaches  its  maximum  just  before  the  next  pull- 
down. The  passing  of  the  flicker  blade  halts  this  expansion  effect 
momentarily. 

Fig.  7  is  an  illustration  of  four  16-mm  frames  taken  of  one  com- 
plete 35-mm  pull-down  cycle.     No.  1  frame  was  taken  immediately 


78  CARVER,  TALBOT,  AND  LOOMIS  [J.  S.  M.  P.  E. 

after  the  pull-down;  No.  2  frame  immediately  before  the  flicker 
blade;  No.  3  frame  just  after  the  flicker  blade;  and  No.  4  frame 
just  prior  to  the  next  pull-down.  In  the  pictures  the  reference  bar 
can  be  seen  protruding  into  the  aperture.  The  movement  of  the 
film  can  be  noticed  by  observing  the  position  of  the  numbers  in  rela- 
tion to  the  reference  bar  at  different  portions  of  the  pull-down  cycle. 
In  the  No.  1  frame,  the  third  column  of  figures  from  the  left  is  masked 
completely  by  the  reference  bar;  in  No.  2  frame,  this  column  of 


FIG.  8.     Scene  used  for  high-speed  screen  pictures.    The  encircled  portion 

is  the  target. 


figures  has  moved  out  almost  into  view.  In  No.  3  frame,  the  film 
appears  to  be  in  about  the  same  position  as  in  No.  2  frame.  This  is 
due  to  the  hesitation  or  even  slight  retraction  of  this  heat-expansion 
effect  as  the  flicker  blade  passes  between  the  light  and  the  film.  In 
No.  4  frame,  the  third  column  of  numbers  is  in  full  view. 

The  lateral  displacement  or  change  of  curl  produced  by  the  ab- 
sorption of  heat  in  the  emulsion  layer  is  a  normal  phenomenon,  and 
takes  place  with  all  types  of  film,  i.  e.,  it  is  the  same  for  fine-grain 
positive  as  for  the  older  type  of  positive,  and  it  takes  place  to  an 
equal  extent  in  all  manufacturers'  films  that  have  been  tested.  It  is 


July,  1943]  EFFECT  OF  HIGH- INTENSITY  ARCS  79 

dependent  upon  the  heat  intensity  and  the  density  of  the  image; 
the  higher  the  heat  intensity,  the  greater  is  the  displacement.  Like- 
wise, the  greater  the  density,  the  greater  is  the  displacement,  since 
more  heat  is  absorbed.  Strange  as  it  may  seem,  the  displacement  is 
independent  of  the  natural  curl  of  the  film — a  film  having  a  high 
positive  curl  will  be  displaced  to  the  same  extent  as  a  film  with  little 
or  no  curl. 

Effect  of  ''Negative  Drift"  on  the  Appearance  of  the  Screen  Image. — 
It  will  be  of  interest  now  to  examine  what  effect  this  "negative  drift," 


FIG.  9.     Enlargement  of  target. 

as  it  is  frequently  referred  to,  has  upon  the  quality  of  the  screen 
image.  In  order  to  demonstrate  this,  the  high-speed  camera  with  a 
telephoto  lens  was  focused  upon  a  portion  of  the  screen  image,  as 
shown  in  Fig.  8.  The  portion  of  the  screen  image  encircled  in  the 
above  figure  consists  of  a  focusing  chart,  an  enlargement  of  which 
appears  in  Fig.  9.  The  projector  was  focused  to  produce  a  sharp 
image  upon  the  screen.  As  stated  before,  this  required  that  the  lens 
be  focused  upon  a  plane  0.01  inch  toward  the  lamp  from  the  aperture. 
The  images  appeared  sharp  to  an  observer  a  few  feet  from  the  screen. 
There  was,  of  course,  some  lack  of  definition  due  to  the  extreme 
magnification.  When  the  16-mm  high-speed  pictures  were  pro- 
jected, it  was  seen  that  for  each  pull-down  cycle  the  35-mm  screen 


80  CARVER,  TALBOT,  AND  LOOMIS  [J.  S.  M.  P.  E. 

image  was  out  of  focus  when  it  first  came  into  view.  It  then  became 
sharper  and  sharper  until,  after  the  flicker  blade  and  just  prior  to 
the  next  pull-down,  the  image  was  in  sharp  focus.  A  series  of  four 
frames  taken  from  this  16-mm  high-speed  film  is  shown  in  Fig.  10. 


FIG.    10.     Enlargement  of  four  individual  frames  from   high-speed   screen 

pictures. 

(1)     Immediately  after  the  pull-down. 
(2}     Immediately  before  the  flicker  blade. 
(5)     Just  after  the  flicker  blade. 
(4)     Just  prior  to  the  next  pull-down. 

As  before,  the  four  frames  represent  different  portions  of  the  pull- 
down cycle.  No.  1  frame  was  taken  immediately  after  the  pull- 
down; No.  2  frame  immediately  before  the  flicker  blade;  No.  3 
frame  just  after  the  flicker  blade;  and  No.  4  frame  just  prior  to  the 
next  pull-down. 

The  appearance  of  the  screen  image  with  different  focus  settings 
of  the  projector  lens  was  tested  using  a  set-up  as  shown  in  Fig.  11. 


July,  1943] 


EFFECT  OF  HIGH- INTENSITY  ARCS 


81 


A  cord  was  wound  about  the  focusing  knob  of  the  projector  lens  and 
attached  to  an  indicator  on  the  screen  in  such  a  manner  that  the 
exact  focal  setting  of  the  projector  lens  appears  in  the  16-mm  pictures 
of  the  35-mm  screen  image.  In  operation  the  projector  is  started 
and  the  image  thrown  on  the  screen  with  the  projector  lens  focused 
+0.02  inch.  The  high-speed  camera  is  started  and  as  soon  as  it  has 
attained  maximum  speed,  the  focus  of  the  projector  lens  is  gradually 
changed  to  a  focus  of  —0.02  inch,  the  movement  being  recorded  by 
the  indicator  on  the  screen. 


FIG.  11.     Set-up  for  recording  the  setting  of  the  35-mm  projector 
lens  on  the  high-speed  pictures  of  the  screen  image. 

With  the  projector  focused  on  the  positive  or  lens  side  of  the  aper- 
ture, the  image  is  in  sharp  focus  only  immediately  after  the  pull- 
down, since  at  this  point  it  is  nearest  to  the  plane  on  which  the  pro- 
jector lens  is  focused.  As  the  film  in  the  aperture  drifts  away  from 
this  original  position  or  toward  the  negative  plane  nearer  the  arc 
lamp,  the  film  moves  beyond  the  depth  of  focus  of  the  lens  and  the 
image  appears  out  of  focus.  A  series  of  four  frames  taken  from  this 
portion  of  the  film  is  shown  in  Fig.  12.  In  these  pictures  the  indi- 
cator shows  that  the  projector  lens  was  focused  at  about  +0.008 


82 


CARVER,  TALBOT,  AND  LOOMIS 


[J.  S.  M.  p.  E. 


inch  or  on  a  plane  0.008  inch  toward  the  lens  from  the  aperture.  As 
the  focus  of  the  projector  lens  is  changed  to  the  negative  or  lamp  side 
of  the  aperture,  the  effect  is  the  opposite.  Here  the  image  comes  into 
view  out  of  focus  and  changes  steadily  to  sharp  focus.  This  is  shown 
in  Fig.  13.  In  these  pictures  the  indicator  shows  that  the  projector 


FIG.  12.     Enlargement  of  four  individual  frames  from  high-speed  screen  pic- 
tures, with  projector  lens  focused  at  +0.008  inch. 

lens  was  focused  at  about  —0.005  inch  or  on  a  plane  0.005  inch  toward 
the  lamp  from  the  aperture. 

The  reason  why  the  projected  images  appear  sharpest  when  the 
projector  is  focused  on  the  negative  plane  is  not  understood  defi- 
nitely. It  is  stated  simply  as  an  observation  repeated  many  times 
with  various  films,  projectors,  and  operators.  It  may  be  that  the 
film  in  the  aperture  is  in  a  state  of  rapid  movement  during  the  first 
one-half  or  three-quarters  of  the  pull-down  cycle  due  to  this  heat 


July,  1943] 


EFFECT  OF  HIGH- INTENSITY  ARCS 


83 


expansion  effect.  It  is  only  after  this  expansion  has  taken  place  that 
the  film  remains  relatively  stationary.  Possibly  the  eye  prefers  to 
focus  upon  the  image  during  that  portion  of  the  cycle  in  which  the 
film  is  relatively  free  from  motion  even  though  this  period  represents 
but  a  fraction  of  the  entire  cycle. 


FIG.  13. 


Enlargement  of  four  individual  frames  from  high-speed  screen  pic- 
tures, with  projector  lens  focused  at  —0.005  inch. 


All  the  film  which  we  have  described  has  been  perfectly  normal. 
No  in-and-out  of  focus  was  observed  upon  the  screen,  and  excellent 
projection  quality  was  obtained  in  spite  of  the  negative  drift  observed 
with  the  high-speed  movies.  The  effect  has  been  obtained  with 
film  of  all  manufacturers  and  with  many  types  of  experimental  film. 
The  effect  is  apparent  at  all  heat  intensities  above  850  °F  as  mea- 
sured by  our  thermocouple  using  the  particular  print  with  which  we 
experimented  most.  In  spite  of  the  fact  that  sharp  pictures  were 
obtained  even  though  this  negative  drift  was  occurring,  nevertheless 


84  CARVER,  TALBOT,  AND  LOOMIS  [J.  S.  M.  P.  E. 

it  was  certainly  true  that  the  focusing  had  to  be  far  more  carefully 
done  with  the  high  temperatures,  when  the  negative  drift  was  large, 
than  with  the  low  temperatures,  when  it  was  absent. 

The  "ln-and-0ut  of  Focus"  Phenomenon. — Up  to  this  point  the 
work  that  has  been  presented  might  be  regarded  as  largely  of  aca- 
demic interest,  its  purpose  being  to  contribute  to  our  knowledge  of 
the  normal  operation  of  films  in  35-mm  projectors  operating  at  high 
heat  intensities.  However,  much  trouble  of  a  serious  nature  has 
been  encountered  in  the  trade  with  a  condition  that  has  come  to  be 
known  as  the  "in-and-out  of  focus"  difficulty.  In  a  number  of 
theaters,  particularly  in  the  de  luxe  houses,  it  has  been  impossible  at 
times  to  keep  the  image  in  sharp  focus  upon  the  screen.  The  effect 
is  exactly  what  the  designation  "in-and-out  of  focus,"  implies;  that 
is  to  say,  the  image  is  perfectly  sharp  the  greater  part  of  the  time  but 
occasionally  goes  out  of  focus  momentarily.  Usually  the  first  few 
projections  of  prints  subject  to  this  difficulty  are  normal.  After 
four  or  five  projections  or  thereabouts,  and  for  several  succeeding 
projections,  it  may  become  difficult,  if  not  impossible,  to  keep  the 
picture  in  sharp  focus. 

It  was  some  time  after  this  difficulty  was  encountered  before  the 
mechanism  by  which  it  took  place  was  discovered.  Since  it  occurred 
most  frequently  with  high-intensity  arc  projectors  which  often  em- 
boss the  film,  many  believed  that  the  focusing  difficulties  were  asso- 
ciated with  this  embossing.  However,  it  is  a  matter  of  record  that 
the  difficulty  may  occur  in  the  initial  projection  of  a  print  on  which 
there  is  no  embossing  or  distortion  of  any  kind.  Likewise  this  in- 
and-out  of  focus  difficulty  disappears  with  repeated  projections  dur- 
ing which  time  the  embossing  of  the  film  increases  gradually. 

Again  it  was  by  high-speed  analysis  of  film  movements  in  the 
aperture  that  the  true  cause  of  the  difficulty  was  discovered.  We 
were  able  eventually  to  obtain  high-speed  pictures  of  film  in  the  gate 
of  a  projector  at  the  exact  instant  the  picture  was  seen  to  go  out  of 
focus  on  the  screen.  The  difficulty  of  obtaining  such  pictures  may 
be  realized  by  considering  that  even  during  bad  in-and-out  of  focus 
trouble  only  relatively  few  frames  of  an  entire  roll  exhibit  the  defect 
and  it  is  impossible  to  tell  beforehand  when  the  trouble  is  about  to 
occur.  The  time  required  to  expose  100  feet  of  film  in  a  high-speed 
camera  is  about  3  seconds,  and  once  the  camera  is  started  the  entire 
roll  must  be  run  off.  Therefore,  most  of  our  shots  show  the  action 
of  perfectly  normal  film.  High-speed  aperture  pictures  of  film  sub- 


July,  1943]  EFFECT  OF  HIGH- INTENSITY  ARCS  85 

ject  to  this  difficulty  show  that  the  great  majority  of  frames  behave 
in  a  normal  manner,  i.  e.,  enter  the  gate  in  a  state  of  slightly  positive 
curl  and  expand  to  a  state  of  negative  curl.  The  projector  is,  there- 
fore, focused  on  this  negative  plane.  Suddenly,  however,  a  few 
frames  come  into  position  in  the  normal  manner,  start  to  expand, 
and  then,  before  reaching  the  plane  of  critical  focus,  jump  back  again 
into  a  state  of  positive  curl.  These  frames,  because  of  their  position 
at  the  end  of  the  cycle,  are  outside  the  plane  of  sharp  focus  of  the 
projector  lens,  and  their  images  are  therefore  more  or  less  completely 
out  of  focus  on  the  screen. 

In  order  to  determine  what  factors  caused  certain  films  to  behave 
in  this  manner,  the  variables  of  processing  and  projection  were 
studied  that  were  thought  to  have  any  bearing  on  the  subject.  Of 
the  various  processing  variables,  only  one  was  found  to  have  any 
influence  on  the  in-and-out  of  focus  effect — the  amount  of  moisture 
left  in  the  film  after  drying.  If  the  film  is  not  dried  sufficiently  the 
in-and-out  of  focus  effect  is  increased  greatly.  This  and  other  ob- 
servations have  led  us  to  believe  that  the  sudden  shift  in  curl  of  the 
frames  that  appear  out  of  focus  is  due  to  a  drying-out  of  the  emulsion 
under  the  influence  of  the  high  heat  intensity  in  the  aperture.  It  is 
believed  that  the  reason  why  insufficiently  dried  films  exhibit  the 
in-and-out  of  focus  defect  is  that  (1)  there  is  more  moisture  in  the 
emulsion,  which  therefore  contracts  more  on  losing  this  moisture,  and 
(2}  the  moisture  tends  to  make  the  film  base  softer  at  high  tempera- 
ture, thereby  offering  less  resistance  to  the  pull  of  the  emulsion  than 
if  the  film  base  were  drier.  These  effects,  due  to  insufficient  drying, 
formerly  caused  some  real  difficulty  with  the  use  of  certain  fine-grain 
films.  These  emulsions  reached  the  point  of  sensible  dryness  in  the 
drying  cabinet  in  about  one-third  the  time  required  for  the  older 
type  of  film.  As  a  consequence  some  of  the  laboratories  used  milder 
drying  conditions  for  the  fine-grain  film  in  order  to  cause  it  to  dry 
in  the  same  position  in  the  cabinet  as  the  type  previously  used.  Thus, 
even  though  the  emulsion  appeared  dry  there  was  certainly  more 
moisture  both  in  the  emulsion  layer,  and  particularly  in  the  support, 
than  in  the  case  of  films  dried  under  the  older  conditions.  Upon 
correcting  these  drying  conditions  much  of  the  in-and-out  of  focus 
difficulty  disappeared. 

The  various  factors  in  the  projection  of  film  that  might  influence 
the  in-and-out  of  focus  effect  on  the  screen  were  also  studied.  These 
were  found  to  be  the  characteristics  of  the  lens,  the  angle  of  pro- 


86 


CARVER,  TALBOT,  AND  LOOMIS 


[J.  S.  M.  P.  E. 


jection,  and  the  heat  intensity.  In  general,  the  more  critical  the 
lens,  the  more  carefully  it  must  be  focused.  Thus  an  //2.0  coated 
lens  gives  a  picture  of  superb  quality  if  the  lens  is  focused  with  ex- 
treme care,  but  the  depth  of  focus  is  so  small  that  a  slight  misad- 
justment  of  the  lens  causes  small  movements  of  the  film  in  the  aper- 
ture to  be  noticeable  on  the  screen.  Likewise  a  steep  angle  of  pro- 
jection produces  the  same  effect  as  decreasing  the  depth  of  focus  of 
the  lens. 


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FIG.  14.  Effect  of  Aklo  heat-absorbing  filter  on  the  heat  inten- 
sity at  the  aperture  of  a  35-mm  projector  and  on  the  light  intensity  at 
the  screen.  The  "aperture  temperatures"  are  the  temperatures 
reached  by  the  thermocouples  when  placed  at  the  center  of  the  aper- 
ture. The  per  cent  light  distribution  indicates  the  ratio  of  the  illu- 
mination at  a  point  5  per  cent  of  the  screen  width  from  the  edge  of  the 
screen  to  the  illumination  at  the  center  of  the  screen. 

The  third  factor,  the  heat  intensity,  was  found  to  be  of  great  im- 
portance. It  has  been  observed  many  times  that  films  exhibiting  the 
in-and-out  of  focus  effect  upon  the  screen  at  heat  intensities  of  1700  °F 
would  project  satisfactorily  if  the  heat  intensities  were  reduced  to 
1250°F.  High  heat  intensities  cause  the  expansion  and  contraction 
forces  operating  on  the  emulsion  to  be  more  violent  in  nature  and,  at 
the  same  time,  soften  the  film  base  so  that  it  is  less  able  to  withstand 
them. 

One  obvious  method  of  reducing  the  heat  intensities  of  these  high- 
intensity  lamps  is  to  insert  a  heat-absorbing  filter  between  the  lamp 
and  the  projector.  Fig.  14  shows  the  reduction  of  heat  and 


July,  1943]  EFFECT  OF  HIGH- INTENSITY  ARCS  87 

effected  by  this  procedure.  The  abscissa  values  correspond  to  the 
various  positions  of  the  condenser  lens.  The  low  numbers  refer  to  a 
position  close  to  the  arc,  thus  giving  a  large  spot  and  consequently 
low  heat  intensity  and  light  values.  At  the  point  of  maximum  heat 
and  light  or  at  a  condenser  setting  of  about  No.  6,  the  insertion  of 
the  heat-absorbing  filter  has  effected  a  23.5  per  cent  reduction  in  heat 
intensity  with  a  reduction  of  but  14  per  cent  in  light  at  the  center  of 
the  screen. 

As  the  result  of  this  work,  we  feel  justified  in  making  two  recom- 
mendations to  the  trade : ,  one  concerning  heat  intensities  and  the 
other  dealing  with  the  drying  of  film.  It  is  recommended  that  the 
heat  intensity  at  the  aperture  of  a  projector  be  kept  down  to  ap- 
proximately 1250°F  by  the  use  of  heat-absorbing  glass*  or  other 
means.  It  is  recommended  also  that  processing  laboratories  dry 
their  films  more  thoroughly,  taking  into  consideration  the  fact  that 
the  film  base  must  be  dried  as  well  as  the  emulsion.  It  should  be 
pointed  out,  however,  that  under  certain  conditions  overdrying  of 
films  may  result  in  "spoky"  rolls,  a  defect  that  is  discussed  in  the 
paper,  "Film  Distortions  and  Their  Effect  upon  Projection  Quality."1 

Acknowledgment. — In  conclusion,  we  wish  to  give  full  acknowl- 
edgment to  Mr.  Eldon  E.  Moyer  for  the  time  and  skill  expended 
in  taking  these  high-speed  motion  pictures,  and  to  Dr.  Alfred  C. 
Robertson  and  Dr.  Geoffrey  Broughton  for  many  suggestions  con- 
tributed to  the  work. 

REFERENCE 

1  CARVER,  E.  K.,  TALBOT,  R.  H.,  AND  LOOMIS,  H.  A.:  "Film  Distortions  and 
Their  Effect  upon  Projection  Quality,"  /.  Soc.  Mot.  Pict.  Eng.,  XLI  (July,  1943), 
p.  88. 

*  A  piece  of  Corning  'Extra  Light  Shade  Aklo  heat-absorbing  glass  4x/4  inches 
in  diameter  and  1.2  mm  thick  was  used  in  place  of  the  Pyrex  glass  normally  found 
between  the  lamp  house  and  the  mechanism  of  the  E-7  projector.  To  minimize 
breakage,  the  glass  was  cut  into  five  strips  about  7/8  inch  wide. 


FILM  DISTORTIONS  AND  THEIR  EFFECT  UPON 
PROJECTION  QUALITY* 

E.  K.  CARVER,  R.  H.  TALBOT,  AND  H.  A.  LOOMIS** 


Summary — The  five  most  generally  recognized  types  of  film  distortion  are  dis- 
cussed. These  consist  of  curl,  spokiness,  embossing,  flute  or  long  edges,  and  buckle 
or  short  edges. 

Curl  has  come  to  be  an  accepted  fact  and  is  ordinarily  without  importance  in  pro- 
jection except  when  it  becomes  excessive. 

Spokiness,  sometimes  called  square  rolls  or  hexagonal  rolls,  is  a  phenomenon  ob- 
served when  film  with  a  high  degree  of  curl  is  wound  with  insufficient  tension  to 
keep  the  roll  perfectly  round.  Poor  screen  quality  in  the  case  of  16-mm  films  has  some- 
times been  associated  with  this  defect. 

Embossing  is  due  to  differential  shrinkage  or  hardening  of  the  emulsion  caused  by 
local  absorption  of  heat  in  the  dense  portion  of  the  picture.  Careful  tests  have  failed 
to  show  any  effect  upon  the  screen  such  as  in-and-out  of  focus  due  to  image  embossing. 
Measurements  of  the  magnitudes  of  the  distortions  show  that  these  are  ordinarily 
much  less  than  the  depth  of  focus  of  the  lens. 

Flute,  or  long  edges,  is  more  often  seen  with  safety  film  than  with  nitrate  film.  It 
is  generally  caused  by  a  stretching  of  the  edges  by  recessed  rolls,  by  shrinking  the  center 
of  the  film  with  high-temperature  arcs  on  projection,  or  by  exposing  the  roll  to  exces- 
sively high  humidities,  which -causes  swelling  at  the  edges  ~  Laboratory  tests  as  well 
as  field  experience  indicate  that  fluted  edges  very  rarely  cause  distortion  of  the  images 
on  the  screen. 

Buckle,  or  short  edges,  is  believed  to  be  the  most  serious  type  of  film  distortion. 
It  is  caused  by  greater  loss  of  moisture  or  solvent  from  the  edges  of  the  film  than  from 
the  center.  This  leaves  a  fullness  of  the  center  resulting  in  an  "oil-can"  effect  when 
film  passes  through  the  projector,  thus  producing  pictures  that  go  in-and-out  of  focus 
on  the  screen. 

Buckle  trouble  may  result  from  storing  rolls  of  film  in  packages  that  are  easily 
permeable  to  moisture  vapor  but  it  may  be  avoided  by  the  use  of  impermeable  packaging 
materials. 

i      X 

There  are  several  types  of  film  distortion  commonly  observed  in 
processed  film  in  the  trade.  Of  these  the  most  important  are  curl, 
spokiness,  embossing,  flute  or  long  edges,  and  buckle  or  short  edges. 
They  are  all  caused  by  expansion  or  contraction,  stretching  or  shrink- 
age, of  certain  portions  of  the  film. 

*  Presented  at  the  1942  Fall  Meeting  at  New  York,  N.  Y. 
**  Eastman  Kodak  Company,  Rochester,  N.  Y. 


FILM  DISTORTIONS  89 

Curl. — Curl  has  come  to  be  an  accepted  fact  and  is  ordinarily 
without  importance  in  projection  except  when  it  becomes  excessive. 
It  is  ordinarily  caused  by  shrinkage  of  the  gelatin  emulsion  at  low 
humidities,  when  it  is  known  as  front  curl,  face  curl,  or  positive  curl. 
When  the  emulsion  has  swelled  at  high  humidities  or  the  base  has 
shrunk,  so  as  to  make  the  emulsion  side  convex,  the  curl  is  called 
back  curl  or  negative  curl. 

Spokiness. — Spokiness  is  a  phenomenon  observed  when  film  with  a 
high  degree  of  curl  is  wound  with  insufficient  tension  to  keep  the  roll 
perfectly  round.  The  explanation  appears  to  be  as  follows:  A 
plane  sheet  of  material  can  easily  be  bent  or  curled  in  one  direc- 


FIG.  1.     (Left)  smooth  roll;    (right)  spoky  roll. 

tion  or  another,  but  strongly  resists  bending  in  two  directions  at  the 
same  time.  Thus  when  a  strip  of  curly  film  is  wound  into  a  roll,  there 
is  a  tendency  for  each  layer  to  resist  bending  for  part  of  a  turn  and 
then  to  bend  sharply.  As  successive  layers  are  wound  on,  each  break 
reinforces  the  last  until  a  definite  hump  has  been  formed.  There 
will  be  a  succession  of  these  humps  around  the  roll  giving  a  character- 
istic appearance  when  the  roll  is  viewed  from  the  side.  The  succes- 
sive humps  appear  as  radial  lines,  somewhat  like  the  spokes  of  a  wheel. 
Such  rolls  are  referred  to  as  being  "spoky." 

Sometimes,  due  to  the  fact  that  the  rolls  appear  polygonal  rather 
than  perfectly  round,  they  are  referred  to  as  square,  octagonal,  or 
hexagonal  rolls,  regardless  of  the  exact  number  of  sides  of  the  polygon. 
A  spoky  roll  is  shown  beside  a  smooth  roll  in  Fig.  1. 


90  CARVER,  TALBOT,  AND  LOOMIS  [J.  S.  M.  P.  E. 

Spokiness  occurs  both  with  35-mm  and  with  16-mm  film  but  does 
not  appear  to  cause  -projection  difficulties  with  35-mm  film.  With 
16-mm  film,  possibly  because  there  is  greater  tendency  for  the  spokes 
to  "set"  in  the  film,  or  possibly  because  of  the  lower  pressure  on  the 
gate  shoes  in  the  projectors,  in-and-out  of  focus  effects  are  sometimes 
produced  by  the  film  distortion  resulting  from  spokiness.  Spokiness 
is  generally  the  result  of  overdrying  in  processing,  resulting  in  film  of 
high  positive  curl,  and  of  loose  winding,  which  allows  film  of  high 
curl  to  spoke  more  readily.  We  must  choose,  therefore,  a  middle 
course  between  overdrying  and  underdrying.  The  former  may 
result  in  focusing  difficulties  as  a  result  of  spokiness ;  the  latter  may 
give  thermal  "in-and-out  of  focus"  effects  such  as  described  in  the 
paper,  "Effect  of  High-Intensity  Arcs  upon  35-mm  Film  Projection."1 

Two  distinct  kinds  of  spokiness  may  be  observed.  If  curly  film 
is  wound  with  the  concave  side  out,  the  spokes  visible  on  the  two 
sides  of  the  film  will  always  be  opposite  each  other.  If  the  roll  is 
wound  with  the  concave  side  in,  the  spokes  will  be  alternate.  The 
spokes  seen  on  one  side  of  the  roll  will  never  be  opposite  those  on  the 
other  side  of  the  roll. 

Embossing. — Embossing  was  a  common  defect  prior  to  the  advent 
of  the  rear  type  shutter,  which  came  into  use  at  about  the  same  time 
as  did  the  sound  movies.  It  has  always  been  considered  an  important 
defect  from  the  point  of  view  of  projection  quality.  It  is  obviously 
due  to  differential  heating  of  portions  of  the  image  due  to  varying 
densities  throughout  the  image.  The  blacker  portions  get  hotter 
and  are  shrunken  by  the  heat.  Sometimes  this  effect  is  most  pro- 
nounced at  the  frame  lines,  when  it  becomes  known  as  frame-line 
embossing.  During  the  experiments  discussed  in  the  preceding 
paper,1  considerable  heavy  embossing  was  produced  by  the  extreme 
arc  temperatures  used,  but  in  no  case  was  the  embossing  sufficient 
to  cause  any  focusing  difficulties  in  the  film.  Measurements  of  the 
actual  depths  of  the  embossing  gave  no  values  higher  than  0.0003 
inch,  which  is  well  within  the  range  of  the  depth  of  focus  of  the  pro- 
jection lenses.  Although  it  may  possibly  be  that  under  certain 
circumstances  embossing  may  increase  the  tendency  of  film  to  show 
in-and-out  of  focus  effects,  we  have  never  found  a  single  case  of  em- 
bossing that  by  itself  gave  focusing  difficulties.  One  fact  was  ob- 
served, however,  that  fresh  film,  and  especially  film  not  thoroughly 
dried,  tended  to  emboss  more  than  well  seasoned  and  dried  film. 
Since  it  is  also  a  fact  that  insufficient  drying  and  seasoning  tends  to 


July,  1943]  FILM  DISTORTIONS  91 

produce  in-and-out  of  focus  troubles  from  other  causes,  we  sometimes 
find  that  film  that  has  been  embossed  has  also  shown  in-and-out  of 
focus  troubles. 

Flute  or  Long  Edges. — The  fourth  type  of  film  distortion,  flute  or 
long  edges,  is  now  seen  more  often  with  safety  film  than  with  nitrate 
film.  A  typical  example  of  flute  or  long  edge  film  is  shown  in  Fig.  2. 
It  is  caused  by  shrinking  the  center  of  the  film  without  shrinking 
the  edges  or,  conversely,  by  stretching  the  edges. 

(a)  Flute  from  shrinkage  of  the  center  of  the  film:  When  film,  es- 
pecially safety  film,  is  projected  repeatedly  at  high  heat  intensities, 
the  center  tends  to  shrink  more  than  the  edges,  causing  a  particular 
type  of  flute  often  known  as  "twist,"  since  a  strip  of  film  stretched 
between  two  points  gives  the  appearance  of  being  twisted. 


FIG.  2.     Flute,  or  long  edge,  in  cine  film. 

(b)  Flute  from  stretching  the  edges  of  the  film  by  means  of  recessed 
rolls:  The  edges  of  the  film  are  often  stretched  in  processing  machines 
by  pulling  the  film  too  tightly  over  recessed  rolls  while  the  film  is  wet 
or  while  it  is  hot. 

(c)  Flute  from  stretching  the  edges  of  the  film  by  the  use  of  twisted 
strands:  Occasionally  processing  machines  are  designed  in  which  the 
film  is  turned  between  each  pair  of  rollers  so  that  the  emulsion  side 
will  never  be  in  contact  with  the  rollers.     If  the  distance  between 
the  rollers  is  too  short  this  twist  puts  an  additional  strain  upon  the 
edges  of  the  film  which  often  produces  flutes. 

(d)  Flute  from  stretching  the  edges  of  the  film  through  swelling  of  the 
edges:  Flute  is  sometime  produced  in  raw  film  if  a  tightly  wound  roll 
is  exposed  to  very  high  humidities.     Moisture  is  absorbed  by  the 


92 


CARVER,  TALBOT,  AND  LOOMIS 


[J..S.  M.  P.  E. 


edges  of  the  film  but  does  not  travel  far  into  the  center.  This  means 
that  the  edges  increase  in  thickness  and  each  layer  builds  up  on  the 
one  under  it.  Even  though  this  thickening  of  a  single  layer  of  film 
may  amount  to  only  0.00001  inch,  there  are,  nevertheless,  650  layers 
in  a  1000-ft  roll  of  film.  The  increased  thickness  of  each  layer  builds 
up  on  those  below  it  so  that  the  edges  of  the  roll  will  have  a  diameter 
0.0065  inch  greater  than  the  center  and  this  increased  diameter  can 
occur  only  by  stretching  the  edges  of  the  film. 


FIG.  3.     Buckle,  or  short  edges,  in  cine  film. 

Buckle  or  Short  Edges. — The  kind  of  distortion  that  has  caused  by 
far  the  greatest  amount  of  trouble  with  35-mm  film  is  short  edges. 
At  the  Eastman  Company  the  term  "buckle"  is  reserved  entirely  for 
this  type  of  distortion,  although  in  the  trade  almost  any  type  of  dis- 
tortion is  frequently  referred  to  as  "buckle."  Fig.  3  shows  a  typical 
example  of  buckle  produced  by  short  edges.  It  is  ordinarily  pro- 
duced whenever  a  film  containing  a  sufficient  amount  of  water  or 
residual  solvent  is  wound  tightly  and  permitted  to  dry  so  rapidly 
that  the  moisture  can  not  diffuse  from  the  center  toward  the  edges 
as  rapidly  as  it  is  taken  away  from  the  edges.  The  edges  shrink  as 


July,  1943]  FILM  DISTORTIONS  93 

they  dry  and  may  become  permanently  distorted.  The  effect  is 
worse  with  film  having  a  high  potential  shrinkage  than  with  modern 
low  shrink  film,  but  even  this  film  can  be  buckled  due  to  moisture 
losses  alone  if  conditions  are  right. 

The  use  of  ordinary  cardboard  boxes  caused  by  the  shortage  of  tin 
for  shipping  film  from  laboratories  to  exchanges  offers  ideal  condi- 
tions for  the  formation  of  buckle.  The  freshly  processed  film,  often 
in  equilibrium  with  50-60  per  cent  relative  humidity,  often  may  be 
exposed  to  humidities  as  low  as  10-15  per  cent  due  to  the  high  mois- 
ture permeability  of  the  cardboard.  Experiments  have  shown 
that  conditions  such  as  described  above  will  almost  invariably  buckle 
moist  film,  whereas  film  that  has  been  thoroughly  dried  in  processing 
will  not  buckle  as  readily.  If  the  film,  before  being  placed  in  plain 
cardboard  containers,  is  wrapped  in  an  envelope  of  a  highly  moisture- 
resistant  paper,  this  tendency  to  buckle  is  practically  eliminated. 
New  types  of  cardboard  boxes  in  which  a  highly  moisture-resistant 
layer  is  incorporated  in  the  box  itself  will  probably  protect  the  film 
even  better  than  these  moisture-proof  envelopes. 

The  reason  why  short  edges  are  so  much  more  likely  to  produce  in- 
and-out  of  focus  effects  upon  the  screen  than  any  other  kind  of  film 
distortion  is  that  these  short  edges  always  leave  a  fullness  in  the 
center  of  the  film  that  produces  an  "oil-can"  effect.  The  center  of 
the  film  is  free  to  bend  in  one  direction  or  the  other.  It  is  this  un- 
certainty as  to  the  direction  in  which  it  will  bend  that  leads  to  the  in- 
and-out  of  focus  effect  upon  the  screen.  Film  showing  in-and-out  of 
focus  due  to  this  particular  effect  can  sometimes  be  corrected  by 
changing  the  moisture  content  of  the  film  so  as  to  give  it  a  potential 
tendency  to  curl  in  either  one  direction  or  the  other.  As  long  as  it 
always  curls  in  the  same  direction  while  it  is  in  the  gate,  no  in-and- 
out  of  focus  will  be  observed.  Such  film  can  further  be  corrected  by 
stretching  the  edges.  This  can  be  done  by  passing  the  film  over  an 
internally  heated  flat  roller  which  shrinks  the  center  and  stretches 
the  edges  slightly. 

It  is  our  hope  that  this  discussion  will  not  only  help  to  clarify  the 
nomenclature  of  different  types  of  film  distortions,  but  that  by  help- 
ing us  to  understand  the  causes  of  these  distortions,  will  result  in 
better  projection  and  better  entertainment. 

REFERENCE 

1  CARVER,  E.  K.,  TALBOT,  R.  H.,  AND  LOOMIS,  H.  A.:  "Effect of  High-Intensity 
Arcs  upon  35-Mm  Film  Projection,"  /.  Soc.  Mot.  Pict.  Eng.,  XLI  (July,  1943),  p.  69. 


CARBON  ARC  PROJECTION  OF  16-MM  FILM* 


W.  C.KALB** 


Summary. — Characteristics  of  the  high-intensity  arc  as  applied  to  the  projection 
of  16-mm  film  are  described.  Carbon  trim,  quality  of  light,  magnification,  optical 
speed,  power  of  the  projection  lamp,  and  the  intensity  and  distribution  of  the  screen 
light  are  also  discussed. 


Projection  of  16-mm  film  has  passed  beyond  the  limitations  of  the 
living  room  and  the  small  classroom.  It  is  now  shown  before  groups 
of  such  size  that  enlargement  to  a  screen  image  several  feet  in  width 
is  essential  to  satisfactory  presentation.  This  has  created  the  need 
for  a  large  volume  of  projection  light  to  provide  the  recommended 
level  of  screen  brightness,  a  need  that  has  been  met  in  a  highly  satis- 
factory manner  by  the  adaptation  of  the  high-intensity  carbon  arc 
to  16-mm  projection. 

HIGH-INTENSITY  PROJECTION  LAMP 

The  projection  lamp  developed  for  this  purpose1  is  a  direct-current 
lamp  operated  through  a  rectifier  from  a  110- volt,  single-phase,  a-c 
supply,  with  a  current  demand  of  less  than  15  amperes  from  the 
supply  line.  The  6-mm  X  8-inch  positive  carbon  and  5.6-mm  X 
6-inch  negative2  are  designed  to  operate  at  30  amperes  d-c  with  28 
volts  across  the  arc.  The  burning  life  of  this  trim  is  approximately 
one  hour,  ample  for  the  projection  of  a  2000-ft,  16-mm  reel  at  sound 
speed  of  24  frames  per  second. 

Fig.  1  shows  the  spectral  energy  distribution  of  the  light  from  this 
arc.  The  composition  of  the  positive  carbon  core  is  somewhat  differ- 
ent from  that  of  high-intensity  positives  used  for  35-mm  projection, 
increasing  the  proportion  of  light  emission  at  longer  wavelengths. 


*  Presented  at  the  1942  Fall  Meeting  at  New  York,  N.  Y. 
**  National  Carbon  Company,  Cleveland,  Ohio. 


94 


CARBON  ARC  PROJECTION 


95 


This  modification  is  made  to  adapt  the  color-quality  of  the  light  to 
color-film  processed  for  projection  by  incandescent  light,  which  is 
customary  in  the  production  of  16-mm  color-film.  Color-temperature 
of  the  screen  light  is  approximately  4450  °K,  giving  excellent  color 
reproduction. 

The  lamp  mirror  is  designed  to  focus  the  arc  crater  image  at  the 
film  aperture  with  a  magnification  of  4x/2 : 1  which  effectively  covers 
the  aperture.  The  beam  divergence  is  sufficient  to  fill  the  2-inch, 
//1. 6  lens  extensively  used  for  16-mm  projection. 


VIOLET        BLUE          GREEN        YELLOW    ORANGE 


RED 


4000 


5000  6000 

WAVE   LENGTH  IN  ANGSTROM  UNITS 


7000 


FIG.  1.  Spectral  energy  distribution  of  light  projected 
on  screen  from  the  high-intensity  carbon  arc  developed 
for  16-mm  projection. 


SCREEN  LIGHT 

This  high-intensity  arc  lamp,  operated  with  a  2-inch,  //1. 6  lens  but 
without  shutter,  film,  or  heat  filter,  projects  2300  lumens  to  the 
screen.  A  representative  figure  for  shutter  transmission  on  commer- 
cial types  of  16-mm  projectors  is  60  per  cent,  and  80  per  cent  is  a 
representative  transmission  factor  for  the  type  of  heat-filter  used  on 
16-mm  carbon  arc  projectors.  The  screen  light  available  with  an 
//1. 6  lens,  shutter  running  and  filter  in  place,  is  therefore  about  1100 
lumens.  This  is  obtained  with  80  per  cent  side- to-center  distribution 
of  screen  brightness,  which  is  about  the  optimum  of  good  projection 
practice.  The  corresponding  screen  illumination  with  other  lenses, 
calculated  on  the  basis  of  relative  /  values,  is  about  700  lumens  with 


96  W.  C.  KALB  [j.  s.  M.  p.  E. 

an  //2.0  lens  and,  with  an  //2.8  lens,  about  360  lumens.  Some  pro- 
jectors have  no  heat-filter  but  use  a  rear  shutter,  or  blower,  or  a 
combination  of  the  two,  to  maintain  low  film  temperature.  With 
this  construction  somewhat  greater  screen  illumination  may  be  ex- 
pected, other  factors  being  equal. 

Calculated  values  are  given  in  Table  I  showing,  for  various  widths 
of  screen  image,  the  brightness  in  foot-lamberts  at  the  center  of  the 
screen  obtained  under  the  stated  conditions  with  high-intensity 
carbon  arc  projection.  The  figures  given  above  for  screen  illumina- 
tion are  used  as  the  basis  for  this  table,  assuming  80  per  cent  side- 
to-center  distribution  of  the  light  on  the  screen. 

TABLE  I 

Foot-Lamberts  at  Center  of  Screen  Image  of  Specified  Width 

Matte  surface  screen  of  75%  reflectivity 
Shutter  running — transmission  60  per  cent 
Heat-filter  of  80  per  cent  light  transmission 
No  film  in  projector 

Width  of 
Screen  Image  Foot-Lamberts  at  Center  of  Screen 

(Feet)  2-In.,  //1. 6  Lens  3-In.,  //2.0  Lens  4-In.  //2.8  Lens 

4*/2  63.0  40.0  20.6 

5  51.0  32.5  16.7 

6  35.5  22.5  11.6 

7  26.0  16.6  8.5 

8  20.0  12.7  6.5 

9  15.75  10.0  5.15 

10  12.75  8.1  4.2 

11  10.5  6.7 

12  8.85  5.65 

13  6.9  4.4 

14  6.5 

15  5.65 

16  5.0 

LENSES 

Lenses  listed  as  available  on  carbon  arc,  16-mm  projectors  range 
from  3/4  inch  to  4  inches  in  focal  length.  The  sizes  usually  supplied 
as  standard  equipment  are  2-inch,  //1. 6  and  3-inch,  //2.O.  Struc- 
tural limitations  on  some  projectors  necessitate  the  use  of  approxi- 
mately the  same  effective  diameter  for  lenses  of  all  focal  lengths  so 
that  increase  in  focal  length  is  accompanied  by  decrease  of  lens  speed. 
However,  projectors  are  available  with  lenses  of //1. 6  speed  in  focal 
lengths  ranging  from  2  inches  to  3l/z  inches. 


July,  1943] 


CARBON  ARC  PROJECTION 


97 


The  use  of  a  projection  lens  with  focal  length  greater  than  the  2- 
inch  or  3-inch  lens  usually  supplied  with  16-mm  projectors  is  seldom 
necessary  although  it  may  occasionally  be  advantageous  in  locations 
where  seating  arrangement,  shape  of  room,  permanent  projection 
booth,  or  other  condition  necessitates  a  long  throw  from  projector 
to  screen.  Increase  in  length  of  throw  with  a  given  lens  increases 
the  width  of  the  screen  image  proportionately  and  may  result  in  a 
larger  image  than  is  desirable.  Furthermore,  the  screen  brightness 
is  decreased  in  inverse  proportion  to  the  change  in  area  of  screen 


FIG.  2.     Seating  plan  for  8-ft  screen;   capacity 
220. 


image.  Increase  of  focal  length  of  lens,  on  the  other  hand,  allows 
the  throw  to  be  increased  in  proportion  to  the  change  in  focal  length, 
without  changing  the  size  of  the  screen  image.  However,  if  the  lens 
of  greater  focal  length  is  also  lower  in  speed  (//value),  less  light  will 
be  thrown  on  the  screen.  Should  the  resulting  screen  brightness 
be  below  the  recommended  level  it  is  usually  preferable  to  seek  some 
means  of  locating  the  projector  closer  to  the  screen  to  permit  use  of 
the  standard  projection  lens. 

The  normal  optical  speed  of  the  16-mm  carbon  arc  projection  lamp 
being //1. 6,  little  is  gained  by  using  a  projection  lens  of  less  than  2- 


98 


W.  C.  KALB 


[J.  S.  M.  P,  E. 


inch  focal  length  in  order  to  obtain  higher  lens  speed  and  more  light 
on  the  screen.  Some  increase  in  optical  speed  of  the  lamp  can  be 
obtained,  to  make  effective  higher  lens  speed,  by  decreasing  the  dis- 
tance from  mirror  to  aperture  and  increasing  that  from  mirror  to  arc. 
However,  the  principal  occasion  for  using  a  lens  of  less  than  2-inch 
focal  length  is  where  the  projector  must  be  located  relatively  close  to 
the  screen  and  a  projected  light-beam  of  wide  angle  is  needed  to 
obtain  the  desired  width  of  screen  image. 


FIG.  3.     Seating  plan  for  11.3-ft  screen;   capacity  412. 

Data  on  screen  light  given  throughout  this  paper  are  based  upon 
untreated  lenses.  Lenses  that  have  been  treated  to  reduce  reflection 
losses  and  improve  the  transmission  factor  are  not  commercially 
available  for  16-mm  projection  at  the  present  time.  However,  car- 
bon arc  projection  of  16-mm  film  with  untreated  lenses  meet  rec- 
ommended standards  of  projection  practice  for  audiences  of  such 
size  that  situations  are  seldom  encountered  in  which  there  is  need 
for  treated  lenses  to  provide  a  satisfactory  intensity  of  screen  illumi- 
nation. 


July,  1943] 


CARBON  ARC  PROJECTION 
SIZE  OF  AUDIENCE 


99 


The  SMPE  Committee  on  Non-Theatrical  Equipment  has  rec- 
ommended3 certain  procedures  and  conditions  to  be  observed  in  the 
presentation  of  16-mm  motion  picture  film  to  provide  a  picture  that 
can  be  viewed  to  good  advantage  by  everyone  present.  Among 
the  recommendations  made  are  the  following : 

(i)  Distance  of  farthest  spectator  from  screen  should  not  exceed  6  times  the 
width  of  screen  image. 


,16  FOOT     , 

rsCREEffl 


FIG.  4.     Seating  plan  for  16-ft  screen;  capacity  856. 


(2)     Distance  of  nearest  spectator  from  screen  should  not  be  less  than  twice  the 
width  of  screen  image. 

(5)     Viewing  angle  of  no  spectator  should  be  greater  than  30  degrees. 

(4)  Optimum   screen  brightness,    10   foot-lamberts   measured  with  shutter 
running  but  without  film. 

(5)  Limits  of  screen  brightness,  not  more  than  20  foot-lamberts  or  less  than 
5  foot-lamberts,  measured  as  above. 

(6)  Color-temperature  of  the  light  delivered  to  the  screen  to  be  in  the  range 
from  3000°  to  4700°K. 

(7)  The  use  of  matte  type  of  screen  "in  all  cases  where  a  projector  of  adequate 
illuminating  power  can  be  obtained." 


100  W.  C.  KALB 

The  report  further  points  out  that  a  2-inch, //1. 6  lens  fills  the  screen 
at  a  distance  equal  to  5L/4  times  the  screen  width. 

From  Table  I  it  may  be  observed  that,  with  a  matte  surface  screen 
of  75  per  cent  reflectivity  and  a  2-inch,  //1. 6  lens,  high-intensity  car- 
bon arc  projection  of  16-mm  film  provides  the  maximum  recom- 
mended level  of  screen  brightness  with  an  image  8  feet  in  width  and 
fills  a  16-foot  screen  at  the  minimum  limit  of  brightness.  The  cal- 
culated image  width  at  optimum  brightness  of  10  foot-lamberts  is 
11.3  feet.  Color-temperature  of  the  light  is  within  the  range  rec- 
ommended by  the  committee. 

Figs.  2,  3,  and  4  represent  seating  plans  conforming  to  the  rec- 
ommended limits  of  viewing  angle  and  distance  from  screen  for  the 
three  conditions  of  screen  width  and  brightness  named  in  the  pre- 
ceding paragraph.  Seating  capacities  are  based  upon  the  use  of  20- 
inch  seats,  32  inches  back  to  back,  with  a  limit  of  14  seats  between 
aisles  as  prescribed  by  the  laws  of  some  states.  Fig.  2  shows  that 
advantageous  presentation  of  16-mm  film  can  be  made  with  high- 
intensity  carbon  arc  projection,  at  maximum  recommended  screen 
brightness,  before  an  audience  of  at  least  220  persons.  Presentation 
at  optimum  screen  brightness  can  be  made  before  412  seated  specta- 
tors with  the  seating  plan  shown  in  Fig.  3  and,  at  the  acceptable  screen 
brightness  of  5  foot-lamberts,  before  an  audience  of  856  seated  as 
indicated  in  Fig.  4. 

Carbon  arc  projectors  are  now  available  from  several  of  the  larger 
manufacturers  of  16-mm  projection  equipment.  The  increased  screen 
size  that  can  be  adequately  illuminated  by  these  carbon  arc  projectors 
greatly  extends  the  utility  of  16-mm  film  for  educational,  commercial, 
and  other  purposes.  It  makes  practicable  the  showing  of  a  16-mm 
picture  before  a  comfortably  seated  audience  of  several  hundred  under 
conditions  conforming  to  the  best  standards  of  projection  practice. 

REFERENCES 

1  STRONG,  H.  H. :    "A  High-Intensity  Arc  for  16-Mm  Projection,"  J.  Soc.  Mot. 
Pict.  Eng.,  XXXIII  (Nov.,  1939),  p.  569. 

2  LOZIER,  W.  W.,  AND  JOY  D.  B. :    "A  Carbon  Arc  for  the  Projection  of  16-Mm 
Film,"  /.  Soc.  Mot.  Pict.  Eng.,  XXXIV  (June,  1940),  p.  575. 

8  "Report  of  the  Committee  on  Non-Theatrical  Equipment,"  /.  Soc.  Mot. 
Pict.  Eng.,  XXXVII  (July,  1941),  p.  22. 


THE  PRACTICAL  SIDE   OF  DIRECT  16-MM   LABORATORY 

WORK* 


LLOYD  THOMPSON** 


Summary. — Laboratory  practice  for  direct  16-mm  production  differs  somewhat 
from  35-mm  methods.  Thiriy-five-mm  laboratory  practice  is  confined  largely  to  nega- 
tive-positive, and  35-mm  color  is  done  mostly  by  special  service  laboratories  and  not 
by  the  studio  or  release-print  laboratories. 

Direct  16-mm  production  calls  for  the  reversal  type  of  processing,  the  negative- 
positive  method,  and  color  developing.  Some  producers  own  laboratories  for  doing 
the  first  two,  but  color  is  processed  by  the  manufacturer.  However,  independent  labo- 
ratories are  printing  color.  This  paper  describes  how  some  of  these  processes  are 
used  in  direct  16-mm  production,  especially  when  the  methods  differ  from  conven- 
tional 35-mm  practices. 


There  have  been  a  lot  of  theories  expounded  as  to  how  16-mm 
laboratory  work  should  be  done.  A  number  of  them  have  been  based 
upon  anticipation  of  what  the  film  manufacturers  may  be  able  to 
offer  in  the  future.  But  we,  the  people  engaged  in  making  16-mm 
motion  pictures  in  order  to  earn  a  living,  can  not  wait  until  all  these 
problems  have  been  worked  out.  Sometimes  we  have  to  forget  the 
theory  as  worked  out  by  the  best  laboratories  doing  35-mm  work  and 
use  a  method  that  will  do  the  job  even  though  it  may  not  conform  to 
theory. 

This  does  not  mean  that  we  are  not  grateful  for  the  theory  as 
worked  out  by  these  laboratories  and  practiced  by  the  producers  of 
35-mm  film,  because  we  are.  A  great  many  of  their  theories  work 
equally  well  in  16-mm  practice,  and  so  the  problem  becomes  one  of 
when  should  we  use  35-mm  methods  on  16-mm  films  and  when  should 
we  disregard  the  methods  and  theories  and  start  using  some  other 
method  of  production  or  laboratory  procedure.  The  answer  is  prob- 
ably quite  simple.  Begin  by  using  the  procedure  that  is  recom- 
mended, and  if  it  does  not  work  try  something  else.  To  say  that 


*  Presented  at  the  1942  Fall  Meeting  at  New  York,  N.  Y.  , 
**  The  Calvin  Company.  Kansas  City,  Mo. 


101 


102  L.  THOMPSON  [j.  s.  M.  p.  E. 

such  a  cut-and-try  method  of  arriving  at  a  standard  should  be  a 
standard  for  all  time  to  come  would  be  foolish.  The  procedures  out- 
lined in  this  paper  have  been  used  in  actual  production  work  and  are 
being  used  today.  We  constantly  try  out  new  ideas  and  new  meth- 
ods and  when  such  a  method  proves  itself  to  be  better  or  more  prac- 
ticable, the  new  procedure  is  adopted. 

Laboratory  practice  for  direct  16-mm  work  may  be  divided  into 
several  divisions: 

(1)  Original  photography. 

(2)  Sound-tracks. 
(3}     Prints. 

Each  of  these  may  be  further  subdivided.  We  shall  begin  with 
original  photography  as  it  is  known  at  the  present  time : 

(1)  Black  and  white. 

(a)  Reversal. 

(b)  Negative  and  positive. 

(2)  Color. 

Most  of  the  recognized  16-mm  producers  today  use  reversal  film 
in  shooting  their  original  black-and-white  pictures.  However,  there 
is  a  growing  tendency  to  use  Kodachrome  even  for  black  and  white. 
In  such  cases  the  original  is  made  in  color  and  the  black-and-white 
prints  are  made  from  dupe  negatives.  There  are  several  things  to 
recommend  the  procedure. 

The  arguments  for  using  reversal  film  for  the  original  picture  have 
been  listed  before,  but  we  may  summarize  them  briefly  by  saying 
that  reversal  film  gives  finer-grained  originals  and  excellent  tone 
quality.  Dirt  spots  do  not  show  up  as  objectionably  as  on  negative 
film,  and  the  original  film  can  be  more  easily  handled  and  spliced  be- 
cause 16-mm  splices  made  on  reversal  film  do  not  show  up  on  the  screen 
as  they  do  with  negative  film.  The  first  cost  of  reversal  is  less.  The 
laboratory  set-up  for  16-mm  reversal  film  is  well  standardized  through- 
out the  world,  and  one  can  be  assured  of  getting  fairly  consistent 
results  at  any  of  these  laboratories.  Sixteen-millimeter  reversal 
film  is  readily  accessible  almost  anywhere.  The  material  lends  it- 
self well  to  making  dupe  negatives  so  that  the  original  can  be  pre- 
served. 

Some  of  the  objections  that  have  been  raised  to  the  use  of  reversal 
film  are  that  it  does  not  have  as  much  latitude  as  the  negative-positive 
process.  It  is  said  to  be  more  critical  in  exposure.  The  photog- 
rapher does  not  have  the  corrective  latitude  in  making  the  prints  after 


July,  1943]  DIRECT  16-MM  LABORATORY  WORK  103 

the  original  has  been  processed  that  he  does  with  negative-positive. 
Some  of  these  things  are  probably  true.  The  film  does  take  special 
handling  in  that  the  lighting  must  be  somewhat  different  from  that 
used  for  negative-positive  film  and  the  exposure  should  be  as  nearly 
correct  as  possible.  However,  this  should  not  work  any  hardship 
on  the  cameraman  who  is  working  with  direct  16-mm  in  a  professional 
way,  because  he  will  probably  be  called  upon  to  handle  both  black- 


FIG.  1.     One-to-one  optical  sound-printer  for  16-mm. 

and- white  and  color.  Color  is  a  reversal  process  and  must  be 
handled  in  much  the  same  way  as  black-and-white  reversal.  For  that 
reason  the  cameraman  must  be  capable  of  using  an  exposure  meter 
in  such  a  manner  that  he  is  able  to  get  consistent  exposures,  and  he 
will  also  be  in  the  habit  of  lighting  for  color-film.  It  is  true  that  there 
is  some  difference  in  the  lighting  for  Kodachrome  and  black-and- 
white  reversal,  but  probably  not  as  much  difference  as  there  is  be- 


104  L.  THOMPSON  [j.  s.  M.  P.  E. 

tween  Kodachrome  and  negative  film.  In  making  a  black-and-white 
production  by  the  reversal  method  the  cameraman  should  always  try 
to  have  enough  film  of  one  emulsion  number  on  hand  to  do  the  com- 
plete job.  He  should  decide  to  what  maximum  density  he  wishes 
the  film  developed  in  order  to  get  the  results  he  wants.  Usually 
this  maximum  density  will  be  approximately  2.1  to  2.3.  He  should 
then  make  tests  with  the  type  of  film  he  expects  to  use,  at  different 
exposure  levels,  and  have  the  film  developed  to  the  correct  maximum 
density.  From  this  series  of  tests  the  cameraman  can  pick  out  the 
exposure  most  nearly  correct  and  thus  set  his  exposure  meter  so  that 
he  can  duplicate  the  results  throughout  the  production.  If  these 
simple  precautions  are  taken  he  should  have  no  trouble  in  getting  con- 
sistent results.  He  should  inform  the  laboratory  doing  his  work 
what  he  is  trying  to  do,  and  it  is  necessary  in  sending  such  black-and- 
white  films  to  the  laboratory  to  enclose  a  note  with  them  stating 
what  is  wanted.  If  the  cameraman  is  having  his  film  developed  to  a 
specific  maximum  density,  he  should  allow  enough  blank  film  on  one 
of  the  rolls  for  the  laboratory  to  run  an  actual  developing  test  so  that 
they  can  be  certain  of  getting  the  correct  density.  In  doing  profes- 
sional work  with  16-mm  film  the  producer  must  remember  that  the 
reversal  laboratories  are  set  up  to  process  amateur  film.  There  are 
some  laboratories  that  use  automatic  exposure  compensation  to  cor- 
rect exposure  errors.  For  average  amateur  films  this  is  perfectly  all 
right,  but  the  maker  of  professional  pictures  usually  does  not  want 
this.  There  are  other  laboratories  that  develop  to  a  certain  maximum 
density  and  depend  upon  the  cameraman  to  give  the  correct  expo- 
sure. Both  methods  have  their  advantages  and  disadvantages,  but 
the  professional  user  will  usually  do  better  to  give  the  film  the  correct 
exposure  and  then  have  it  developed  to  a  specified  maximum  density. 
In  developing  amateur  film  the  reversal  laboratory  receives  each  day 
many  different  emulsion  numbers  from  different  customers.  Some 
of  this  film  may  be  out  of  date,  some  of  it  may  be  almost  out  of  date, 
and  other  rolls  may  be  fresh  film.  Some  of  it  may  have  been  stored 
under  bad  conditions  and  other  rolls  will  have  been  kept  under  ideal 
conditions.  Different  batches  of  emulsion  will  vary,  and  as  a  result 
some  of  the  rolls  may  be  developed  in  such  a  way  that  they  would  not 
meet  standards  of  the  professional.  For  that  reason  it  is  a  good  idea 
to  send  a  test  strip  along  with  each  batch  of  film  sent  in  for  processing 
and  to  specify  the  maximum  density  to  which  the  film  is  to  be  de- 
veloped. 


July,  1943] 


DIRECT  16-MM  LABORATORY  WORK 


105 


The  criticism  has  been  made  of  reversal  film  that  it  does  not  have 
as  much  latitude  as  negative-positive.  Practical  experience  has 
shown  that  if  an  exposure  meter  is  used  consistently  the  latitude  is 
sufficient  for  all  practical  purposes  and  by  making  light-changes  in 
the  prints  the  films  can  be  evened  out  very  successfully.  Extreme 
under-  or  overexposure  is,  of  course,  very  difficult  or  impossible  to 
correct  in  printing.  But  this  may  also  be  true  of  16-mm  negative- 
positive.  Because  of  its  size,  16-mm  film  must  be  more  nearly  cor- 


FIG.  2.      Wet  end  of  a  16-mm  reversal  processing  machine. 

rectly  exposed  than  larger  films,  whether  reversal  or  negative-posi- 
tive. 

The  criticism  has  been  made  also  that  reversal  films  are  not  espe- 
cially suited  for  shooting  under  adverse  conditions.  The  statement 
has  been  made  that  many  times  it  is  impossible  to  light  a  subject 
sufficiently  and  it  is  necessary  to  bring  it  out  by  overdevelopment  of 
the  negative,  and  that  this  can  not  be  done  in  reversal.  This  is  not 
the  case.  There  are  times  when  the  cameraman  does  not  have 
enough  light  on  the  scene  and  yet  he  must  make  the  shot.  In  such  a 
case  he  should  shoot  the  scene  that  does  not  have  sufficient  light  and 


1061  L.  THOMPSON  [j.  s.  M.  p.  E. 

keep  the  film  separate  from  the  rest  of  the  film.  He  should  also  shoot 
some  extra  footage  on  this  particular  scene  at  the  same  exposure  he 
used  in  making  the  test.  He  should  give  this  to  the  laboratory  for 
test  and  ask  them  to  overdevelop  it  so  as  to  give  the  best  results. 
The  laboratory  can  then  take  the  extra  footage  and  run  one  test  or, 
perhaps,  several  tests,  in  order  to  find  exactly  how  much  the  film 
should  be  overdeveloped  in  order  to  get  the  best  results  from  that  par- 
ticular roll.  This  is  extra  work  for  the  laboratory  but  most  labora- 
tories are  willing  to  cooperate.  Such  tests  require  extra  time  and 
when  something  special  is  wanted  the  lab  should  be  allowed  some  ex- 
tra time  in  order  to  perform  the  necessary  tests  to  get  the  best  results. 

While  it  is  possible  to  get  good  results  with  rack-and-tank  develop- 
ing, automatic  machine  processing  gives  more  consistent  results  from 
day  to  day.  Most  producers  of  16-mm  film  will  find  it  to  their  advan- 
tage to  use  the  laboratory  that  offers  machine  processing.  Practically 
all  film  manufacturers  offer  such  a  service,  and  any  of  the  standard 
films  on  the  market  offer  laboratory  service  where  machine  processing 
is  available.  Occasionally  some  16-mm  film  producer  will  attempt 
to  use  an  off -brand  film  or  try  to  process  a  negative  film  as  reversal, 
and  naturally  the  results  are  disappointing.  Standard-brand  films 
should  be  used,  and  certain  types  of  emulsions  will  do  a  better  job 
than  others.  The  user  will  therefore  have  to  learn  which  emulsions 
give  best  results  for  his  purpose  and  he  should  then  try  to  stick  with 
that  particular  type  of  emulsion.  He  should,  of  course,  try  new 
emulsions  as  they  are  offered  from  time  to  time,  and  there  are  times 
when  the  cameraman  wants  some  effects  that  can  be  made  only  by 
using  a  special  emulsion.  He  may  even  want  to  use  positive  film  and 
reverse  it. 

Most  of  the  direct  16-mm  producers  have  probably  started  with 
the  idea  that  the  way  to  shoot  16-mm  commercially  would  be  to  use 
negative  film  and  make  positive  prints  from  it  just  as  they  do  in 
Hollywood.  There  has  been  a  great  deal  of  effort  spent  in  trying  to 
develop  a  laboratory  procedure  that  would  be  entirely  satisfactory 
for  16-mm  commercial  work  done  in  this  manner.  Some  very  good 
work  has  been  done,  but  there  are  still  a  number  of  things  about  the 
process  that  make  it  impracticable  for  most  commercial  purposes. 
The  time  may  come  when  these  defects  will  be  corrected. 

A  great  number  of  developers  have  been  tried  with  negative  film. 
There  are  the  common  borax-type  formulas  which  are  well  known  in 
the  35-mm  industry.  There  have  been  other  special  formulas  in- 


July,  1943] 


DIRECT  16-MM  LABORATORY  WORK 


107 


volving  the  use  of  paraphenylenediamine  and  various  combinations 
of  chemicals.  These  formulas  have  been  worked  out  in  an  attempt 
to  get  fine-grain  quality  from  original  negatives  that  would  match 
the  fine-grain  characteristics  of  reversal  film.  The  use  of  fine-grain 
positive  has  done  a  great  deal  toward  reducing  the  graininess.  Also, 
the  original  negative  can  be  developed  to  a  lower  gamma  and  the 
positive  print  to  a  higher  gamma,  which  makes  for  finer  grain. 

In  developing  16-mm  negative  film  it  is  extremely  important  that 
the  film  be  developed  to  the  correct  gamma.  It  is  important  also 
that  the  processing  be  very  clean  because  dirt  spots  become  very  ob- 
jectionable white  spots  on  the  positive  print.  Negative  film  is  also 


FIG.  3.     The  testometer,  used  for  checking  timing, 
a  time-scale  sensnometer. 


The  left  side  contains 


very  susceptible  to  scratches  and  any  scratch,  no  matter  how  slight, 
either  on  the  back  of  the  base  or  on  the  emulsion  side,  will  show  up 
on  the  positive  print  as  an  objectionable  white  line. 

Because  16-mm  negative  film  is  so  susceptible  to  scratches  and  dirt 
and  because  the  splices  made  in  negative  film  show  up  as  objection- 
able white  lines  on  the  screen,  it  is  extremely  difficult  to  handle  in 
regular  production  work.  The  same  precautions  should  be  observed 
in  shooting  negative  film  as  in  shooting  reversal.  That  is,  it  should 
be  properly  exposed,  different  emulsions  should  not  be  mixed  to- 
gether in  the  same  production  unless  it  is  absolutely  necessary,  and 
the  producer  should  have  the  full  cooperation  of  the  laboratory  in 


108  L.  THOMPSON  [j.  S.  M.  P.  E. 

getting  the  most  out  of  his  negatives.     Machine  processing  is  highly 
desirable. 

At  the  present  time  the  only  commercial  process  for  shooting  16-mm 
color  originals  is  Kodachrome.  Kodachrome  is  developed  only  in 
the  laboratories  of  the  manufacturer  of  the  film,  and  here  we  might 
say  the  customer  has  no  control  over  the  laboratory  practice  in  de- 
veloping the  film.  We  might  also  assume  that  the  customer  needs 
to  take  no  special  precautions  because  the  laboratory  procedure  on 
Kodachrome  will  be  consistent  from  day  to  day,  and  thus  the  results 
will  be  the  same.  This  is  not  exactly  true.  We  in  the  16-mm  busi- 
ness quite  frequently  see  films  that  have  been  shot  by  some  amateur 


FIG.  4.     Using  the  testometer  as  a  sensitometer. 

photographer  to  be  used  in  a  commercial  film.  He  has  taken  no 
special  precautions  as  to  using  one  emulsion  number  throughout  the 
picture  or  through  one  particular  sequence,  or  as  to  sending  all  of  the 
picture,  or  all  of  the  pictures  in  a  sequence,  for  processing  at  one  time. 
As  a  result  we  quite  frequently  see  pictures  in  which  the  color  balance 
changes  considerably.  On  the  other  hand,  we  have  shot  a  number  of 
Kodachrome  pictures  and  have  not  been  annoyed  with  this  change  in 
color  balance  to  any  degree.  However,  there  are  certain  precautions 
to  be  observed.  If  possible,  we  usually  try  to  shoot  an  entire  picture 
on  one  batch  of  emulsion  or  at  least  we  try  to  shoot  one  particular 
sequence  on  one  particular  emulsion  number.  If  possible  we  also 


July.  1943]  DIRECT  16-MM  LABORATORY  WORK  109 

like  to  shoot  one  entire  sequence  or  an  entire  picture  and  send  it  in  for 
processing  all  at  one  time.  The  laboratory  that  develops  our  Koda- 
chrome  film  is  aware  of  the  fact  that  nearly  all  the  Kodachrome  which 
we  send  for  processing  is  of  a  commercial  nature,  and  these 
films  are  never  run  until  they  have  had  a  chance  to  see  the  work  com- 
ing from  the  machine  and  had  a  chance  to  check  it  to  be  sure  that  the 
color  balance  is  correct.  If  the  color  balance  is  slightly  off,  the  films 
are  held  until  it  is  as  nearly  correct  as  possible,  and  then  the  films  are 
run  through.  The  color  balance  is  never  very  far  off,  because  in 
nearly  all  cases  the  films  are  within  very  acceptable  limits.  If  the 
picture  is  to  be  used  for  commercial  purposes  it  is  desirable  that 
these  limits  be  held  within  as  close  tolerances  as  possible.  Here  again 
we  have  found  the  laboratories  perfectly  willing  to  cooperate  in  every 
way  provided  we  tell  them  what  we  are  trying  to  do. 

Just  as  in  35-mm  practice,  there  are  two  types  of  sound-tracks  used 
in  direct  16-mm.  However  in  the  1 6-mm  field  variable-area  predom- 
inates. In  direct  16-mm  there  are  three  types  of  variable-area  tracks 
used  at  the  present  time.  They  are : 

(a)  Negative  tracks. 

(b)  Direct  positive  tracks. 

(c)  Reversal  tracks. 

Variable-area  negative  tracks  are  used  for: 

(1)  Printing  with  original  negatives. 

(2)  Printing  with  dupe  negatives. 

(5)     For  making  positive  prints  for  printing  with  Kodachrome  prints  or  black- 
and-white  reversal  prints. 

Variable-area  direct  positive  tracts  are  used  for : 

(1 )  Printing  directly  to  Kodachrome. 

(2)  Printing  directly  to  black-and-white  reversal  tracks. 
(5)     For  re-recording. 

(4)     For  printing  negative  tracks  where  it  may  be  necessary  to  have  several 
negative  tracks. 

Variable-area  reversal  tracks  are  used  for : 

(I)     Single-system  sound. 
(2}     Re-recording  purposes. 

Variable-area  tracks  are  usually  developed  in  regular  positive  de- 
veloper although  there  have  been  special  formulas  developed  for 
processing  variable-area  tracks.  Since  processing  machines  are 
usually  set  up  with  positive  developer  and  since  these  developers  are 
in  constant  use,  it  is  comparatively  simple  to  keep  the  developer  at 


110  L.  THOMPSON  [J.  S.  M.  P.  E. 

the  correct  potential  at  all  times.  Regular  lib  sensitometric  strips 
can  be  run  through  with  the  processing  during  the  day  and  these 
strips  checked  to  be  sure  that  the  developer  is  in  proper  condition 
before  running  sound-tracks.  If  a  special  developer  is  used  for  sound^ 
track  developing  only,  it  is  necessary  either  to  change  developers  in 
the  tank  or  to  have  a  special  tank  for  sound-tracks  only.  In  either 
case  the  developer  is  not  in  continuous  use,  and  since  there  is  prob- 
ably no  laboratory  with  enough  direct  16-mm  sound-tracks  to  keep  it 
running  constantly,  it  is  necessary  that  a  certain  portion  of  the  day  be 
picked  for  running  sound-tracks.  If  the  developers  must  be  changed 
it  is  necessary  to  check  their  temperature;  also  to  run  either  a  test  of 
the  sound-track  or  a  sensitometric  strip  before  actually  processing 
the  film.  This  takes  a  great  deal  of  time  and  it  is  questionable  as  to 
whether  this  procedure  helps  the  final  result.  If  yellow-dyed  record- 
ing stock  is  used  with  blue  light  (4000  to  4500  angstroms:  Corning 
597)  for  making  the  original  sound-track,  the  usual  procedure  is  to  de- 
velop the  negative  tracks  to  a  density  of  1 .8  to  2.0.  Gamma  is  usually 
1.8  to  1.85.  Positive  prints  made  from  such  negatives  on  fine-grain 
stock  and  developed  to  the  proper  gamma  and  density  will  give  good 
reproduction  and  also  improve  the  noise  level  of  the  positive  track. 
Direct  positive  tracks  are  not  in  general  use  either  in  35-mm  or 
direct  16-mm  productions.  By  direct  positive  track  is  not  meant 
reversal  track,  but  direct  positive  track  produced  optically.  The 
track  is  developed  as  an  ordinary  sound-track,  but  instead  of  getting 
a  negative  track  we  have  a  positive  track,  which  can  be  used  either 
for  play-back  or  for  printing  by  the  black-and-white  reversal  method 
or  with  Kodachrome.  It  is  necessary  to  have  a  special  galvanometer 
for  this  type  of  track.  According  to  theory  such  track  does  not  lead 
to  good  results.  However,  we  have  not  found  that  to  be  exactly 
true.  Since  yellow-dyed  stock  has  been  available  for  recording  sound 
in  direct  16-mm,  it  has  been  possible  to  make  good  direct  16-mm  posi- 
tive tracks  without  very  much  difficulty.  Such  tracks  must  be  prop- 
erly exposed  and  developed  if  good  results  are  to  be  obtained.  The 
density  becomes  rather  critical.  We  have  used  such  tracks  for  a  num- 
ber of  purposes :  for  recording  music  when  the  music  was  to  be  re-re- 
corded on  another  direct  positive  or  negative  track  for  printing;  ,  for 
recording  original  voice  which  was  to  be  used  for  re-recording  before 
printing;  and  for  direct  recording  when  the  recording  was  to  be 
printed  with  Kodachrome  or  with  black-and-white  reversal  prints. 
We  have  also  made  direct  positive  tracks,  and  then  dupe  negatives 


July,  1943]  DIRECT  16-MM  LABORATORY  WORK  111 

from  them  for  making  positive  prints.  We  have  been  told  many  times 
that  some  of  the  things  we  are  doing  are  entirely  wrong  and  we  simply 
should  not  do  them  that  way.  We  have  conducted  a  great  many  ex- 
periments along  this  line  and  are  convinced  that  for  a  number  of  pur- 
poses the  direct  positive  will  work  very  satisfactory  in  direct  16-mm 
recording  work.  If  the  film  is  to  be  used  for  direct  play-back  or  for 
re-recording,  the  density  is  kept  at  1.2  to  1.3.  If  it  is  developed  be- 
yond 1 .4  the  highs  usually  have  a  tendency  to  block  slightly.  If  the 
direct  positive  is  to  be  used  for  printing  with  Kodachrome  or  for 
printing  black-and-white  reversal  prints,  the  density  of  the  direct 
positive  sound-track  can  go  up  to  1.5,  1.6,  or  even  higher.  We  have 
never  found  any  particular  advantage  in  going  beyond  1.5  or  1.6,  as  a 
track  of  this  density  seems  to  be  about  as  quiet  in  the  print  as  one 
that  has  been  developed  to  a  higher  density.  (Some  of  the  new  re- 
cording stock  should  be  developed  to  1.8,  1.9,  or  higher.)  While  it  is 
possible  to  make  direct  positive  tracks  on  regular  positive  release  stock, 
the  developing  becomes  very  critical,  and  for  that  reason  we  have  found 
the  yellow-dyed  stock  to  be  much  more  satisfactory  for  making  this 
type  of  track,  as  well  as  for  other  direct  16-mm  recording.  Direct 
positive  tracks  are  developed  in  positive  developer  the  same  as  the 
variable-area  negative  tracks.  In  production  work  we  attempt  to 
control  the  exposure  of  the  original  recording  so  that  all  tracks  can 
be  developed  a  normal  time  in  the  developer  and  when  different  den- 
sities are  wanted  the  exposure  is  changed  to  give  that  density.  If 
emulsion  numbers  are  closely  watched  and  exposure  lamps  are  care- 
fully checked  and  tested  before  use,  it  is  comparatively  simple  to  get 
whatever  density  is  wanted  from  day  to  day. 

Producers  who  do  not  own  their  own  laboratories  and  must  de- 
pend upon  outside  laboratories  for  developing  their  original  sound- 
tracks can  get  the  same  results  if  they  will  follow  certain  definite 
procedures.  One  complete  session  of  recording  should  be  recorded 
on  one  emulsion  number  if  at  all  possible.  Lamp  currents  should 
be  carefully  adjusted  and  maintained  accurately.  A  test  exposure 
should  be  left  on  one  of  the  rolls  of  film  and  this  roll  clearly  marked 
as  to  how  much  and  where  the  test  will  be  found.  The  density 
wanted  on  the  final  track  should  be  clearly  indicated.  If  it  is  neces- 
sary to  change  emulsions  during  a  session,  this  should  be  clearly 
indicated  and  a  test  left  on  the  new  emulsion  that  is  used.  If  it  is 
necessary  to  change  recorder  lamps  during  a  recording  session,  this 
also  should  be  noted  on  the  film  and  a  test  left  for  the  new  lamp  as 


112  L.  THOMPSON  [j.  a  M.  P.  E. 

well  as  the  old  one.  All  recording  lamps  should  be  checked  photo- 
graphically before  being  used.  We  have  found  that  recording  lamps 
that  are  supposed  to  be  prefocused  and  correctly  adjusted  will  vary 
as  much  as  four  or  five  points  in  density.  For  that  reason  we  have 
made  up  a  special  jig  for  our  recorders,  and  whenever  we  receive  new 
lamps  they  are  checked  in  this  jig  with  a  master  lamp  which  we  know 
gives  us  maximum  exposure.  Before  doing  this  we  had  a  great  deal 
of  difficulty  in  trying  to  keep  our  densities  correct  over  a  period  of 
time.  All  new  lamps  are  first  checked  in  the  jig  and  then  inserted  in 
the  recorder ;  then  a  short  photographic  test  is  made  of  them  and  the 
density  given  by  each  of  the  lamps  is  marked  on  the  lamp.  In  this 
way  if  the  lamp  burns  out  during  recording  it  is  possible  to  select 
another  lamp  having  exactly  the  same  characteristics,  and  proceed 
with  the  recording.  It  might  seem  that  this  is  taking  a  lot  of  un- 
necessary care,  but  if  the  film  is  to  be  used  for  commercial  purposes 
we  feel  that  everything  should  be  as  nearly  correct  as  possible,  and 
it  is  much  cheaper  to  make  these  checks  than  it  is  to  make  retakes. 
These  precautions  ar  e  necessary  for  a  producer  operating  his  own 
laboratory  even  though  he  has  full  knowledge  of  any  irregularities  that 
may  take  place.  Commercial  producers  who  send  their  work  to  com- 
mercial laboratories  must  take  the  same  precautions  if  they  expect 
the  results  to  be  uniform. 

Variable-area  reversal  tracks  are  usually  used  with  single-system 
sound  recording.  There  are  several  reasons  why  the  reversal  system 
can  not  be  used  in  place  of  the  direct  positive  tracks  about  which  we 
have  been  talking.  Most  galvanometers  do  not  have  enough  light 
in  them  to  expose  positive  film  or  yellow-dyed  recording  stock  suffi- 
ciently for  the  reversal  process.  Even  though  the  galvanometer 
may  have  enough  light  for  exposing  the  stock  for  reversal  processing, 
the  exposure  and  the  developing  become  very  critical.  Unless  the 
exposure  and  the  developing  are  absolutely  correct  on  positive  film 
or  recording  stock,  the  sound  either  loses  a  great  deal  of  volume  be- 
cause the  clear  portions  do  not  clear  out  completely,  or  the  highs  are 
cut  off  by  overexposure  or  incorrect  developing.  If  panchromatic  film 
or  Kodachrome  is  used  for  recording  sound  by  this  method,  these  de- 
fects are  not  nearly  so  noticeable.  In  this  case  the  exposure  is  not  so 
critical  although  enough  exposure  should  be  given  to  clear  out  the 
clear  portions  of  the  track,  otherwise  the  volume  level  becomes  very 
low  and  the  background  noise  becomes  objectionable.  The  danger 
of  overexposure  is  not  so  great  when  this  type  of  film  is  used.  It  is 


July,  1943]  DIRECT  16-MM  LABORATORY  WORK  113 

perfectly  satisfactory  to  record  sound  on  panchromatic  film  or  on 
Kodachrome  when  the  picture  is  being  taken  at  the-  same  time. 
However,  most  people  will  not  want  to  use  regular  panchromatic 
film  for  recording  the  sound  only,  as  it  will  be  somewhat  expensive 
and  the  results  will  not  be  as  good  as  is  obtained  with,  for  instance,  a 
direct  optical  positive.  Such  film  can  be  used  for  re-recording  pur- 
poses quite  satisfactorily  but  it  is  not  suitable  for  re-printing  by  the 
reversal  system.  Sound  made  by  the  reversal  system  has  a  slight 
tendency  toward  distortion  due  to  the  spreading  of  the  light-beams 
and  the  procedure  used  in  reversal  processing.  Therefore,  if  an  origi- 
nal reversal  sound-track  is  printed  again  by  the  reversal  method,  this 
distortion  tends  to  build  up  and  become  rather  objectionable.  Single- 
system  sound  shot  on  Kodachrome  is  also  quite  satisfactory  when  the 
proper  exposure  is  given  and  when  the  sound  is  used  as  a  direct  play- 
back. Such  sound-tracts  are  not  suitable  for  printing  to  another 
Kodachrome  duplicate.  If  such  sound-tracks  must  be  re-printed,  the 
best  method  at  the  present  time  seems  to  be  to  re-record  the  sound  to 
the  black-and-white  track  and  then  print  from  that.  Re-recording 
the  sound-track  directly  on  the  print  is  also  satisfactory,  but  in  such 
case  type  A  stock  must  be  used  instead  of  duplicating  stock,  as  the 
dupe  stock  is  too  slow  to  be  used  in  most  recorders. 

Variable-density  has  not  been  used  a  great  deal  in  direct  16-mm 
work.  Probably  the  widest  use  of  variable-density  in  16-mm  has  been 
with  single-system  cameras.  It  has  been  necessary  that  these 
cameras  use  negative  film  as  they  were  unable  to  get  enough  exposure 
of  the  reversal  type  of  emulsion  to  get  a  sound-track.  Since  prac- 
tically all  the  variable-density  sound  has  been  made  with  single- 
system  cameras,  it  does  not  seem  that  anyone  has  done  very  much  re- 
search on  the  developing  and  printing  of  variable-density  direct  16- 
mm  sound.  Since  most  people  shooting  single-system  variable- 
density  sound  are  interested  in  getting  a  good  picture,  negatives  are 
nearly  always  developed  to  get  the  most  out  of  the  pictures  and  let 
the  sound  take  care  of  itself. 

After  the  original  photography  has  then  been  shot  and  the  original 
sound  has  been  made  there  is  then  the  question  of  getting  prints,  and 
the  question  of  getting  good  prints  has  been  one  of  the  biggest  prob- 
lems in  the  16-mm  field.  However,  this  problem  has  been  pretty 
well  solved  during  the  past  few  years  and  practice  is  becoming  fairly 
well  standardized.  We  shall  consider  first  the  problem  of  black-and- 
white  prints. 


114  L.  THOMPSON  [j.  s.  M.  P.  E. 

The  first  print  wanted  from  an  original  is  usually  a  work  print. 
If  the  original  is  reversal  or  Kodachrome,  a  reversal  black-and-white 
work  print  is  made — all  on  one  light.  An  inexpensive  grade  of  film 
such  as  positive  is  used  for  printing,  and  this  is  reversed.  This  gives 
a  positive  image  which  is  easy  for  the  editor  to  work  with.  Some 
originals  are  now  shot  on  stock  with  edge  numbers  in  which  case  they 
can  be  printed  on  the  work  prints.  This  is  the  most  satisfactory 
method  of  editing  except. that  the  use  of  edge-numbered  stock  for 
originals  is  not  yet  universal.  Rush  prints,  as  they  are  known  in  the 
35-mm  field,  are  usually  not  used  in  16-mm  work.  Originals  are 
usually  projected  for  this  purpose,  and  then  those  scenes  that  are  to 
be  used  are  cut  out,  spliced,  and  a  work  print  made. 

Suppose  the  original  was  made  on  black-and-white  reversal  film  or 
Kodachrome.  The  first  method  of  making  black-and-white  release 
prints  from  original  reversal  film  was  the  reversal  process.  There 
were,  of  course,  dupe  negatives,  but  the  early  dupe  negatives  were  far 
from  satisfactory.  The  prints  obtained  with  the  reversal  system  were 
good  enough  that  most  persons  were  not  able  to  tell  them  from  origi- 
nals. For  that  reason  the  reversal  process  was  used  almost  exclu- 
sively for  several  years  in  making  black-and-white  prints  from  re- 
versal originals,  as  well  as  in  making  sound-prints.  The  method  is 
still  capable  of  giving  excellent  results,  and  when  only  a  few  prints 
are  wanted  from  an  original  it  is  probably  the  most  satisfactory  and 
the  most  economical  method  of  making  them.  The  procedure  for 
making  black-and-white  reversal  prints  is  well  standardized.  They 
can  be  turned  out  in  the  shortest  possible  time  and  there  is  no  added 
expense  of  making  a  dupe  negative. 

The  most  satisfactory  solution  to  printing  direct  16-mm  sou  ad 
seems  to  be  the  one-to-one  optical  sound-printer.  It  gives  good 
definition,  and  there  is  no  shrinkage  or  creepage  problem.  The  re- 
sults are  consistent  from  day  to  day.  The  printer  can  be  used  for 
printing  all  direct  16-mm  tracks.  If  sound  is  to  be  added  to  black- 
and-white  reversal  prints  it  is  necessary  to  have  a  positive  track  of 
some  sort  or  other.  This  positive  track  can  be  a  positive  from  a  nega- 
tive or  it  can  be  a  direct  optical  positive.  The  density  of  the  track 
should  be  1.5  or  more;  in  any  event  the  density  of  the  original  track 
for  making  reversal  prints  should  be  quite  high.  If  a  reversal  print  is 
made  of  an  original  track  of  low  density,  there  is  a  tendency  to  lose 
considerable  volume.  In  order  to  avoid  losing  this  volume  it  is  neces- 
sary to  print  with  enough  light  to  clear  out  the  clear  portions  com- 


July,  1943]  DIRECT  16-MM  LABORATORY  WORK  115 

pletely.  With  this  rather  strong  printing  light  the  dark  portions  of 
the  track  also  have  a  tendency  to  become  lighter  in  the  print,  and  if 
the  original  is  light  at  the  beginning  this  will  be  accentuated  in  the 
print.  The  track  is  likely  to  become  noisy  either  from  a  lack  of  den- 
sity in  the  dark  portions  or  because  of  density  in  the  clear  portions. 
However,  original  sound-tracks  having  a  density  of  1.5  or  better 
print  very  satisfactorily  on  reversal  film.  Printing  reversal  tracks 
from  original  optical  positive  seems  to  have  the  same  cancelling  ef- 
fect upon  distortion  as  printing  negatives  to  positives. 

If  a  number  of  black-and-white  prints  are  wanted  from  an  original 
black-and-white  reversal  film  or  from  Kodachrome  film,  the  cheapest 
and  most  satisfactory  method  of  obtaining  them  at  the  present  time 
is  by  making  a  fine-grain  dupe  negative  on  panchromatic  duplicating 
film.  This  dupe  negative  is  then  used  for  printing  positives.  The 
most  satisfactory  material  for  printing  the  positives  at  the  present 
time  seems  to  be  the  fine-grain  positive  films  that  are  available.  In 
making  a  16-mm  dupe  negative  it  is  necessary  to  be  especially  careful 
that  no  blemishes  or  dirt  occur  in  the  processing,  since  they  will  show 
up  in  the  final  print  and  be  quite  objectionable.  It  is  almost  neces- 
sary to  use  a  step  printer  with  pilot-pin  movement  in  making  these 
dupe  negatives  if  proper  contact  and  screen  steadiness  are  to  be 
achieved.  After  a  steady  dupe  negative  is  made,  it  can  then  be 
printed  on  a  good  continuous  printer  with  satisfactory  results. 
Continuous  printers  seem  to  be  quite  suitable  for  making  any  print 
where  several  printing  processes  are  not  required. 

At  this  point  it  might  be  well  to  discuss  the  construction  of  16-mm 
printers  and  print  rooms.  Since  several  types  of  film  are  used  and 
since  they  can  be  worked  under  different  safe-lights,  we  have  found 
it  advantageous  to  work  each  printer  in  a  separate  room.  Each 
operator  can  use  a  safe-light  suited  to  the  stock  he  is  using  without 
interfering  with  any  other  operator.  In  some  cases  we  have  found  it 
advantageous  to  use  white-light  loading-dark-room  printing  print- 
ers. Original  films  are  usually  edited  to  lengths  of  390  feet  on  400-ft 
reels.  Our  printers  are  all  constructed  to  take  these  reels  and  we  use 
cores  only  for  the  raw  stock.  By  keeping  originals  on  reels  it  makes 
them  easy  to  handle,  store,  and  check. 

In  order  to  make  consistently  good  dupe  negatives  it  is  necessary 
to  use  sensitometric  strips  for  checking  density  and  gamma.  If  the 
final  release  prints  are  to  be  of  uniform  density  throughout,  it  is  neces- 
sary to  use  some  sort  of  machine  for  checking  light-changes.  This 


116  L.  THOMPSON  [j.  S.  M.  P.  E. 

check  is  probably  more  important  in  making  dupe  negatives  from  16- 
mm  originals  than  it  is  in  35-mm  work.  In  our  own  laboratory  we 
use  a  machine  called  a  testometer,  which  was  manufactured  especially 
for  us  by  the  Baker  Motion  Picture  Apparatus  Company.  It  is  a 
combination  time-scale  sensitometer  and  light-testing  machine.  Un- 
like many  machines  which  make  exposure  tests  on  alternate  light 
changes  on  the  printer  board,  this  machine  has  been  built  to  cover  a 
complete  range  from  one  end  of  the  scale  to  the  other  on  our  particu- 
lar printers. 

It  is  important  that  this  machine  be  used  for  timing,  instead  of 
inspecting  the  original  film  visually  and  then  having  the  operator 
judge  the  correct  light-change,  because  an  original  picture  made  on 
16-mm  reversal  film  may  have  a  number  of  different  types  of  film  in  it. 
It  may  have  several  different  brands  of  reversal  stock  developed  in 
different  laboratories.  This  is  not  recommended,  but  such  things 
happen.  It  may  contain  titles  made  on  positive  film.  It  may  con- 
tain shots  taken  from  35-mm  film  and  reduced  to  16-mm  positive 
film. 

The  reversal  process  has  a  tendency  to  deposit  a  slight  yellow  tone 
in  the  gelatin  of  the  film.  This  strain  will  vary  somewhat  in  the  same 
laboratory  from  day  to  day.  It  will  naturally  vary  from  day  to  day 
with  different  laboratories  and  also  with  different  brands  of  film. 
There  may  be  days  when  there  is  practically  no  stain.  Different 
brands  of  reversal  film  will  also  have  different  tones  due  to  the  char- 
acteristics of  the  emulsion.  Usually  the  finer-grained  films  have  a 
tendency  to  be  slightly  on  the  brown  side.  All  these  things  affect 
the  printing  light,  and  the  operator  will  have  a  very  difficult  time  dis- 
tinguishing between  various  tones  and  setting  his  printer  light  cor- 
rectly. These  tones  are  usually  not  deep  enough  to  be  objectionable 
when  the  picture  is  projected  but  they  are  deep  enough  to  affect  the 
printing  light  considerably. 

The  procedure  used  in  our  laboratory  is  to  make  these  testometer 
exposures  on  reversal  duplicating  film  and  then  have  them  developed 
to  normal  density.  The  testometer  strips  are  then  projected  on 
a  small  screen  with  the  same  intensity  of  illumination  as  would 
be  used  on  a  normal-size  screen.  From  these  tests  we  are  able 
to  pick  the  best  exposure  from  each  test  strip  of  each  scene,  and  a 
dupe  negative  made  in  this  manner  will  usually  print  on  one  light- 
change.  Panchromatic  duplicating  film  is  exposed  in  our  labora- 
tories at  the  same  printing  light  as  reversal  duplicating  film.  This 


July,  1943]  DIRECT  16-MM  LABORATORY  WORK  117 

machine  can  be  used  also  for  checking  color  merely  by  using  the  light 
of  the  proper  color-temperature  with  the  correct  filter. 

Once  the  correct  dupe  negative  has  been  made  from  an  original 
black-and-white  reversal  or  colorfilm  positive,  prints  are  then  made; 
and  if  the  negative  has  been  correctly  made  the  positive  prints  will 
be  of  excellent  quality  with  good  detail,  good  tone  quality,  and  fine 
grain.  Dupe  negatives,  like  original  negatives,  are  very  susceptible 
to  dirt  and  scratches,  and  the  utmost  care  must  be  used  in  handling 
them  because  the  slightest  scratch  or  piece  of  dirt  will  show  up  in  the 
final  print  as  an  objectionable  white  streak  or  spot.  If  such  a  nega- 
tive is  ruined  or  worn  out,  another  negative  can,  of  course,  be  made 
from  the  original,  and  one  can  start  all  over  again.  When  a  large 
number  of  black-and-white  prints  is  wanted,  a  dupe  negative  has  a 
definite  advantage  over  prints  by  other  methods.  If  the  original 
has  been  edited  with  masks  for  trick  effects,  these  masks  are  run  at 
the  same  time.  The  effects  will  then  be  in  the  dupe  negative  and  will 
appear  in  the  positive  prints. 

If  original  negatives  are  used  for  making  positive  prints,  it  is  neces- 
sary to  time  them  for  light-changes  and  then  print  them  just  as  one 
would  print  from  dupe  negatives.  It  is  difficult  to  say  how  many 
prints  can  be  made  from  an  original  negative  before  it  becomes  worn 
or  scratched,  as  this  depends  entirely  upon  the  handling  of  it  and  the 
type  of  printer  used.  The  procedure  for  handling  original  negatives 
and  dupe  negatives,  and  the  printers  used  for  printing  them,  are  con- 
tinually being  improved,  and  as  they  are  improved  more  prints  can 
be  made  from  each  negative. 

At  the  present  time  the  most  successful  method  of  making  color- 
prints  from  original  Kodachrome  is  to  print  on  Kodachrome  duplicat- 
ing film.  As  yet,  the  results  of  making  a  master  print  corresponding 
to  a  dupe  negative  and  making  prints  from  it  are  not  entirely  satis- 
factory. That,  of  course,  would  be  the  ideal  way  of  making  prints, 
but  to  date  all  Kodachrome  prints  are  made  directly  from  the  original 
when  the  best  quality  is  desired.  When  various  laboratories  began 
to  print  Kodachrome,  one  of  the  biggest  worries  was  how  many  prints 
could  be  made  from  the  original  before  it  was  worn  out.  We  do  not 
yet  know  the  answer,  but  there  have  been  instances  where  250 
prints  have  been  made  from  an  original.  There  is  one  thing  peculiar 
about  printing  Kodachrome.  The  base  side  of  the  film  can  become 
quite  badly  scratched  and  abraded,  but  most  of  the  marks  do  not 
show  up  in  the  print.  Small  scratches  or  abrasions  on  the  base  that 


118  L.  THOMPSON 

would  be  utterly  disastrous  to  a  black-and-white  dupe  negative  do 
not  seem  to  print  on  Kodachrome.  It  is  only  when  there  is  dirt  on 
the  film  or  when  the  scratches  become  very  deep  and  black  that  they 
seem  to  show  up  on  the  print.  Ordinary  16-mm  printers  that  have 
been  used  for  black-and-white  printing  only  must  usually  be  con- 
verted before  they  can  be  used  for  printing  Kodachrome.  Koda- 
chrome duplicating  film  takes  a  great  deal  more  light  than  any  other 
film  used  in  16-mm  printing.  Some  printers  can  be  converted  to  give 
the  extra  amount  of  light,  and  if  the  printer  is  still  used  for  printing 
black-and-white,  some  method  must  be  used  for  reducing  the  light  for 
the  other  stock.  This  can  be  done  by  changing  lamps  or  by  using 
neutral  density  filters.  Instruction  for  balancing  the  light  for  Koda- 
chrome printing  can  be  obtained  from  the  Eastman  Kodak  Company, 
but  such  directions  will  probably  serve  only  as  a  guide  in  setting  up 
any  particular  printer.  We  have  set  up  several  printers  for  Koda- 
chrome printing  and  in  each  case  it  has  been  necessary  to  use  a  differ- 
ent filter  set-up,  even  though  the  lamp  temperatures  were  the  same, 
as  nearly  as  we  could  tell  with  the  color-temperature  meter  and  by 
referring  to  the  charts  of  the  lamp  manufacturers.  Once  the  printer 
has  been  balanced  for  color-printing,  it  is  usually  a  good  idea  to  print 
tests  on  it  over  a  period  of  a  week  or  two  and  have  them  processed 
on  various  days  before  putting  the  printer  into  actual  production. 
If  this  is  done  it  may  be  found  that  slight  additional  corrections  are 
desirable  to  give  the  best  average  results.  We  have  already  discussed 
sound-printing  on  black-and-white  reversal  film.  The  printing  of 
sound  on  Kodachrome  film  does  not  seem  to  be  as  critical  as  on  black- 
and-white.  Optical  printers  seem  to  be  the  most  satisfactory  for  the 
sound,  and  the  additional  contrast  gained  is  an  advantage.  Sound 
printed  by  contact  on  Kodachrome  can  also  be  quite  satisfactory. 

A  direct  optical  positive,  or  a  positive  from  a  negative  will  make  a 
good  Kodachrome  print.  The  best  density  of  this  track  seems  to  be 
1.4  to  1.6.  A  few  exposure  tests  should  be  run  on  the  Kodachrome 
and  after  processing  the  print  should  be  played  on  several  reproduc- 
ing units.  Such  tests  should  be  conducted  at  periodic  intervals. 


SOCIETY  ANNOUNCEMENTS 


FIFTY-FOURTH  SEMI-ANNUAL  TECHNICAL  CONFERENCE 
OF  THE  SOCIETY 


At  the  meeting  of  the  Board  of  Governors  held  at  the  Hotel  Pennsylvania, 
New  York,  on  May  3rd,  it  was  decided  to  hold  the  Fifty-Fourth  Semi-Annual 
Technical  Conference  of  the  Society  at  Hollywood.  The  headquarters  will  be  the 
Hollywood-Roosevelt  Hotel,  and  the  dates  October  18th  to  22nd,  inclusive. 

The  Chairman  of  the  Papers  Committee  for  the  Meeting  will  be  Dr.  C.  R.  Daily. 
The  personnel  of  the  Papers  and  other  Committees  will  be  announced  in  the  next 
issue  of  the  JOURNAL. 

Those  intending  to  submit  papers  for  the  Conference  should  communicate  as 
early  as  possible  with  Dr.  Daily,  at  Paramount  Pictures,  Inc.,  5451  'Marathon  St., 
Hollywood,  Calif. 

MID-WEST    SECTION 

Due  to  the  declining  activity  of  the  Mid- West  Section  of  the  Society  during  the 
past  several  years,  the  Board  of  Governors,  at  their  meeting  at  New  York  on 
May  3rd,  took  action  to  discontinue  the  Section. 

There  will  thus  be  two  Local  Sections  of  the  Society:  (1)  the  Atlantic  Coast 
Section,  comprising  members  of  the  Society  resident  in  the  Eastern  and  Central 
Standard  Time  Zones,  and  (2)  the  Pacific  Coast  Section,  comprising  members 
resident  in  the  Mountain  and  Pacific  Standard  Time  Zones.  Members  of  the 
former  Mid- West  Section  will  be  affiliated  with  either  the  Atlantic  Coast  Section 
or  the  Pacific  Coast  Section  according  to  their  places  of  residence. 

MAILING  OF  NOTICES  TO  MEMBERS  OF  THE 
ATLANTIC  COAST  SECTION 

As  the  territory  included  by  the  Atlantic  Coast  Section  of  the  Society  extends 
from  Maine  to  Florida  and  includes  the  Eastern  and  Central  Standard  Time 
zones  (as  the  result  of  the  discontinuance  of  the  Mid- West  Section),  many  of  the 
members  of  the  Section  find  it  impossible  to  attend  the  monthly  meetings  and 
other  functions.  The  situation  has  been  considerably  aggravated  by  the  present 
difficulties  of  transportation. 

For  these  reasons,  as  well  as  for  reasons  of  economy,  the  Board  of  Governors, 
at  the  meeting  held  on  May  3rd  at  New  York,  felt  that  notices  of  meetings, 
routine  letters,  and  other  material  should  be  sent  only  to  members  of  the  Section 
residing  in  the  New  York  metropolitan  area,  since  it  is  from  this  area  that  the 
meetings  draw  practically  all  their  attendance. 

However,  the  Board  provided  also  that  members  not  residing  in  the  New  York 
metropolitan  area  but  who  wish  to  receive  such  notices,  etc.,  may  have  their  names 
continued  upon  the  mailing  list  of  the  Section  by  writing  to  the  office  of  the 
Society,  at  the  Hotel  Pennsylvania,  New  York,  N.  Y. 

119 


120  SOCIETY  ANNOUNCEMENTS 

THE  ASSOCIATION  FOR  SCIENTIFIC  PHOTOGRAPHY 

The  following  announcement  concerning  the  formation  of  The  Association  for 
Scientific  Photography  has  been  received  from  Mr.  Donald  McMaster,  of  Kodak 
Ltd.,  England: 

Within  recent  years  there  has  been  a  ^ery  marked  increase  in  the  use  of  photog- 
raphy as  a  scientific  instrument  in  applied  science  and  industry.  It  is  felt  that 
the  majority  of  workers  in  these  fields  are  working  quite  independently  of  others 
similarly  engaged  and  that  a  new  organization  catering  for  their  special  photo- 
graphic requirements  would  be  of  considerable  value. 

An  Association  for  Scientific  Photography  has  accordingly  been  formed,  mem- 
bership of  which  is  open  to  any  person  actively  engaged  or  interested  in  the  use  of 
kinematography  or  photography  as  a  scientific  instrument. 

The  Committee  of  the  Association  consists  of  the  following  persons :  Prof.  J.  Yule 
Bogue  (Chairman),  S.  Boyle,  Miss  K.  C.  Clark,  G.  A.  Jones,  E.  H.  Le  Mon,  Dr.  H. 
Mandiwall,  C.  D.  Reyersbach,  G.H.  Sewell,  R.  Mc.V.  Weston  (Organizing  Secretary). 

The  aim  of  the  Association  is  not  only  to  promote  interest  in  the  use  of  photog- 
raphy in  all  branches  of  science,  technology,  and  medicine,  but  also  to  assist  its 
members  in  applying  photographic  methods  to  the  solution  of  particular  problems. 

The  Association  proposes  to  establish  what  might  be  termed  an  Information 
Bureau  containing,  as  far  as  possible,  full  particulars  of  the  activities  of  all  mem- 
bers and,  in  suitable  cases,  the  existence  and  whereabouts  of  specialized  photo- 
graphic apparatus  and  equipment.  These  data  will  be  used  by  the  Association 
for  the  benefit  of  members  as  a  "pool"  from  which  information  may  be  drawn  on 
the  very  varied  applications  of  photography  to  research,  industry,  and  teaching. 

Use  will  also  be  made  of  this  information  to  enable  personal  contacts  to  be 
made  between  members  working  in  similar  fields  and  also  to  facilitate  visits  by 
members  who  may  be  using  similar  photographic  procedures,  to  the  laboratories 
of  other  members. 

The  field  covered  by  the  Association  will  be  a  very  wide  one,  and  will  include 
photographic  processes  of  all  kinds,  such  as  radiography,  color  photography,  pho- 
tomicrography, and  in  particular,  sub-standard  cinematography  in  all  its  branches. 

The  Association  will  endeavor  to  obtain  for  members  information  on  practically 
any  photographic  problem  which  may  arise  in  the  prosecution  of  scientific  work. 

Meetings  will  be  arranged  from  time  to  time  at  which  short  papers  will  be 
delivered,  to  be  followed  by  discussion  and  practical  demonstrations  of  apparatus 
and  methods  by  members.  The  frequency  with  which  such  meetings  can  be  held 
will  depend  to  some  extent,  upon  wartime  conditions.  It  is  the  intention  of  the 
Association  to  publish  a  Journal  as  soon  as  circumstances  permit. 

The  Association  is  anxious  to  foster  the  production  of  sub-standard  films  for 
research  and  teaching  purposes,  and  will  endeavor,  as  far  as  possible,  to  raise 
the  standard  of  the  method  of  presentation  of  such  films,  which  at  the  present 
time  is  low.  Members  will  be  able  to  obtain  information  on  methods  of  produc- 
tion and  methods  of  presentation  of  films  of  scientific  interest. 

Further  activities  will  be  undertaken  by  the  Association  according  to  the  de- 
mand made  for  such  services. 

Announcements  of  meetings  will  be  made  from  time  to  time,  and  any  person 
requiring  further  information  or  particulars  of  membership  is  invited  to  com- 
municate with  the  Organizing  Secretary,  R.  Me.  V.  Weston,  whose  present  ad- 
dress is:  Houndwood.  Farley.  Salisbury,  Wilts,  England. 


JOURNAL  OF  THE  SOCIETY  OF 
MOTION   PICTURE   ENGINEERS 

VOLUME  XLI  •         •          •  AUGUST,  1943 

CONTENTS 

PAGE 

Recent  Developments  in  Sound-Tracks 

E.  M.  HONAN  AND  C.  R.  KEITH  "  127 

Operations  of  Army  Air  Force  Combat  Camera  Units  in 
the  Theaters  of  War  R.  JESTER     136 

Developments  in  the  Use  of  Motion  Pictures  by  the 
Navy  W.  EXTON,  JR.     141 

Problems  in  the  Production  of  U.  S.  Navy  Training 
Films  O.  GOLDNER     146 

The  16-Mm  Commercial  Film  Laboratory 

WM.  H.  OFFENHAUSER,  JR.     157 

The  Projection  of  Motion  Pictures  H.  A.  STARKE     183 

Application   and   Distribution   of    16-Mm   Educational 
Motion  Pictures  F.  W.  BRIGHT     190 

The  Fifty-Fourth  Semi-Annual  Technical  Conference  of 
the  Society,  Hollywood,  Calif.,  October  18-22,  1943       195 

Society  Announcements  199 

(The  Society  is  not  responsible  Jor  statements  of  authors.) 


JOURNAL  OF  THE  SOCIETY  OF 
MOTION  PICTURE  ENGINEERS 

SYLVAN  HARRIS,  EDITOR 
ARTHUR  C.  DOWNES,  Chairman 

Board  of  Editors 

JOHN  I.  CRABTREE      ALFRED  N.  GOLDSMITH       EDWARD  W.  KELLOGG 
CLYDE  R.  KEITH       ALAN  M.  GUNDELFINGER     CHARLES  W.  HANDLEY 

ARTHUR  C.  HARDY 
Officers  of  the  Society 
**  President:  HERBERT  GRIFFIN, 

90  Gold  Street,  New  York,  N.  Y. 
*' 'Past-President:  EMERY  HUSE, 

6706  Santa  Monica  Blvd.,  Hollywood,  Calif. 
**Executive  Vice-President:  LOREN  L.  RYDER, 
5451  Marathon  Street,  Hollywood,  Calif. 
^Engineering  Vice-President:  DONALD  E.  HYNDMAN, 

350  Madison  Avenue,  New  York,  N.  Y. 
**  Editorial  Vice-President:  ARTHUR  C.  DOWNES, 

Box  6087,  Cleveland,  Ohio. 
*  Financial  Vice-President:  ARTHUR  S.  DICKINSON, 

28  W.  44th  Street,  New  York,  N.  Y. 
**  Convention  Vice-President:  WILLIAM  C.  KUNZMANN, 

Box  6087,  Cleveland,  Ohio. 
^Secretary:  E.  ALLAN  WILLIFORD, 

30  E.  42nd  Street,  New  York,  N.  Y. 
^Treasurer:  M.  R.  BOYER, 

350  Fifth  Ave.,  New  York,  N.  Y. 
Governors 

*H.  D.  BRADBURY,  411  Fifth  Avenue,  New  York,  N.  Y. 
*FRANK  E.  CARLSON,  Nela  Park,  Cleveland,  Ohio. 
*ALFRED  N.  GOLDSMITH,  580  Fifth  Avenue,  New  York,  N.  Y. 
*A.  M.  GUNDELFINGER,  2800  S.  Olive  St.,  Burbank,  Calif. 
*CHARLES  W.  HANDLEY,  1960  W.  84th  Street,  Los  Angeles,  Calif. 
*EDWARD  M.  HONAN,  6601  Romaine  Street,  Hollywood,  Calif. 
*JOHN  A.  MAURER,  117  E.  24th  Street,  New  York,  N.  Y. 
**WILLIAM  A.  MUELLER,  Burbank,  Calif. 

*HOLLIS  W.  MOYSE,  6656  Santa  Monica  Blvd.,  Hollywood,  Calif. 
**H.  W.  REMERSHIED,  716  N.  La  Brea  St.,  Hollywood,  Calif. 
**JOSEPH  H.  SPRAY,  1277  E.  14th  Street,  Brooklyn,  N.  Y. 
**REEVE  O.  STROCK,  195  Broadway,  New  York,  N.  Y. 

*Term  expires  December  31,  1943. 
**Term  expires  December  31,  1944. 


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Published  monthly  at  Easton,  Pa.,  by  the  Society  of  Motion  Picture  Engineers. 

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Picture  Engineers,  Inc. 


RECENT  DEVELOPMENTS  IN  SOUND-TRACKS* 
E.  M.  HONAN**  AND  C.  R.  KEITHf 

Summary. — Photographs  and  dimensions  are  given  for  a  number  of  types  of 
sound-tracks,  some  of  which  are  in  general  use  and  some  being  experimental  types. 

The  considerable  number  of  types  of  sound-tracks  that  have  come 
into  use  in  the  past  few  years  make  it  desirable  to  agree  upon  stand- 
ard dimensions  and  nomenclature  in  order  to  avoid  confusion.  Steps 
in  this  direction  have  been  taken  with  the  publication  of  "Dimen- 
sional Standards  for  Motion  Picture  Apparatus,"  in  the  JOURNAL  of 
this  Society  (XXIII,  Nov.,  1934,  p.  247)  and  in  a  Bulletin  of  the  Re- 
search Council  of  the  Academy  of  Motion  Picture  Arts  &  Sciences, 
"Standard  Nomenclature  for  Release  Print  Sound-Tracks"  (Novem- 
ber 24,  1937).  However,  in  the  several  years  since  the  publication  of 
these  standards,  the  number  of  types  of  sound-tracks  in  common  use 
has  considerably  increased.  It  is,  therefore,  the  purpose  of  this  paper 
to  publish  illustrations  and  brief  descriptions  of  the  most  commonly 
used  tracks  and  also  some  experimental  tracks  in  order  that  suitable 
dimensions  and  nomenclature  may  be  agreed  upon  and  adopted  as 
standards. 

The  accompanying  illustrations  show  twenty  types  of  sound-tracks 
and  combinations  of  tracks  used  on  35-mm  film.  The  illustrations 
are  grouped  according  to  the  type  of  track  and  without  regard  to  the 
relative  importance  or  extent  of  use.  The  description  of  each  track 
is  intended  primarily  for  identification  since  a  discussion  of  the  rela- 
tive merits  of  the  various  types  would  require  a  very  extensive  paper. 
However,  references  are  given  to  previous  publications  where  more 
complete  descriptions  of  the  tracks  may  be  found.  All  the  illustra- 
tions show  positive  prints. 

The  first  group  of  tracks  shown  are  of  100-mil  variable-density 

*  Presented  at  the  1942  Fall  Meeting  at  New  York,  N.  Y. 
**  Electrical  Research  Products  Division,  Western  Electric  Company,  Inc., 
Hollywood,  Calif. 

t  Electrical  Research  Products  Division,  Western  Electric  Company,  Inc., 
New  York,  N.  Y. 

127 


128 


E.  M.  HONAN  AND  C.  R.  KEITH 


[J.  S.  M.  P.  E. 


type.  It  will  be  noted  that  "100  mil"  and  "200  mil"  refer  to  the 
width  of  film  allotted  to  one  or  more  tracks.  Descriptions  of  the 
"squeeze- track"  and  "push-pull"  features  will  be  found  in  the  refer- 
ences associated  with  tracks  of  these  types.  The  use  of  noise-reduction 
in  variable-density  recording  may  be  observed  on  the  film  as  an  in- 
crease in  average  density  in  those  portions  having  low  modulation, 
although  this  is  not  apparent  in  the  small  sections  shown  in  the  ac- 
companying illustrations. 

(a)  Single  Variable-Density  (100- Mil). — This  is  a  standard  release  track  and  is 
the  same  as  Fig.  1  of  the  Academy  Bulletin.1- 2-  3 


(b)  Single  Variable-Density  Squeeze. — This  is  the  same  as  track  a  except  that 
the  width  is  varied  to  increase  the  volume  range.  It  is  the  same  as  Fig.  2  of  the 
Academy  Bulletin.  The  width  may  be  varied  by  bringing  the  two  outer  margins 
closer  together,  as  shown ;  by  keeping  the  outer  margins  fixed  and  inserting  a  black 
centerline  of  varying  width,  or  by  a  combination  of  the  two  previous  methods. 
Since  the  maximum  track  width  is  76  mils,  the  amount  of  squeeze  illustrated  rep- 
resents a  reduction  of  sound  level  of  only  about  3  or  4  db.4-  5 


A-.076-Y 


(c)  Push-Pull  Variable-Density. — The  two  tracks  are  similar  to  a  but  are  each 
47.5  mils  wide  and  180°  out  of  phase.  This  is  the  same  as  Fig.  7  of  the  Academy 
Bulletin.6 


Aug.,  1943]       RECENT  DEVELOPMENTS  IN  SOUND-TRACKS 

.,04  7  5".    JO 4  7  5; 


129 


(J)  Push-Pull  Variable-Density  Squeeze. — This  is  the  application  of  squeeze- 
track  methods  to  the  push-pull  track,  c.  It  is  the  same  as  Fig.  8  of  the  Academy 
Bulletin.5 


The  next  group  are  of  the  100-mil  variable-area  type.  Each  is 
"Class  A"  unless  otherwise  noted.  (See  track  h.) 

(e)  Unilateral  Variable- Area. — Noise-reduction  is  indicated  by  the  change  in 
width  of  the  right-hand  black  margin.  It  is  the  same  as  Fig.  4  of  the  Academy 
Bulletin.7- 8-  9-  10-  n 


(/)  Bilateral  Variable- Area. — Noise-reduction  is  indicated  by  the  change  in 
average  width  of  the  clear  center  portion  of  the  track.  It  is  the  same  as  Fig.  5  of 
the  Academy  Bulletin.11-  « 


130 


E.  M.  HONAN  AND  C.  R.  KEITH 


[J.  S.  M.  P.  E. 


GO  Duplex-Variable-Area. — Noise-reduction  in  this  case  is  indicated  by  a 
variation  in  the  distance  between  the  two  black  borders.  It  is  the  same  as  Fig.  6 
of  the  Academy  Bulletin.13 


(h)  Push-Pull  Variable-Area — Class  A. — The  term  "Class  A"  means  that  each 
half  of  the  push-pull  record  is  complete  and  may  be  separately  reproduced  with 
comparatively  little  distortion.  In  the  example  shown  each  half  is  a  unilateral 
track  and  the  out-of -phase  relation  is  shown  by  the  fact  that  a  dark  projection  on 
one  side  is  always  exactly  opposite  a  white  indentation  on  the  other  side.  The 
same  effect  is  obtained  if  each  half  of  the  push-pull  track  is  recorded  as  a  bilateral 
variable-area  track.  Noise-reduction  is  indicated  by  a  variation  in  the  distance 
between  the  two  black  borders.  This  is  the  same  as  Fig.  9  of  the  Academy  Bulle- 
tin." 


(i)  Push-Pull  Variable-Area — Class  B. — In  this  case  one-half  of  the  push-pull 
record  represents  only  the  positive  half  of  the  original  wave  and  the  other  the  nega- 
tive half,  so  that  the  two  halves  must  be  reproduced  with  equal  amplitudes  and 
in  opposite  phase  in  order  to  avoid  distortion.  Since  the  print  is  opaque  except 
where  modulated,  the  usual  bias  type  of  noise-reduction  is  not  required.  The 
individual  tracks  may  be  bilateral,  as  shown  in  the  illustration,  or  they  may  be 
unilateral.11-  12'  13 


Aug.,  1943]      RECENT  DEVELOPMENTS  IN  SOUND-TRACKS 


131 


(j)  Push-Pull  Variable-Area — Class  A-B. — In  this  type  of  track  low  modula- 
tion is  recorded  as  Class  A  (each  track  records  both  halves  of  the  original  wave) 
but  as  the  modulation  is  increased  it  is  changed  to  Class  B  by  recording  the  addi- 
tional amplitude  with  the  positive  waves  on  one  track  and  the  negative  waves  on 
the  other.  Noise-reduction  is  not  used  in  this  type  of  sound-track.14 


The  next  group  of  tracks  occupy  a  width  of  200  mils  and  are  con- 
sequently not  used  on  present  standard  combined  sound  and  picture 
prints. 


(k)  200-Mil  Variable-Density. - 
variable-density  tracks.6 


-This  is  a  push-pull  combination  of  two  100-mil 


(1)  200-Mil  Variable-Area  Center  Shutter. — This  consists  of  two  100-mil  bilateral 
Class  A  variable-area  tracks  in  push-pull  relation.  Noise-reduction  is  accom- 
plished by  blocking  out  a  portion  in  the  center  of  each  track.18  !  .  \  ' 


Each  of  the  remaining  combinations  of  tracks  includes  a  "control- 
track"  together  with  one  or  more  sound-tracks.  The  control- track 
is  generally  used  to  vary  the  sound  level  in  the  reproducing  system  in 
such  a  manner  as  to  increase  the  volume  range  or  the  signal-to-noise 


132 


E.  M.  HONAN  AND  C.  R.  KEITH 


[J.  S.  M.  P.  E. 


ratio  or  both.  It  may  be  either  amplitude-  or  frequency-modulated, 
and  may  be  distinguished  in  the  illustrations  by  its  resemblance  to  a 
constant-frequency  record.  The  word  "comprex"  refers  to  a  system 
in  which  automatic  volume  compression  and  expanison  are  used. 

(ni)  100-Mil  Variable-Density  Comprex. — Both  sound  and  control-tracks  are 
50  mils  wide  and  occupy  the  space  normally  used  for  a  standard  single  100-mil 
track.  Track  dimensions  are  the  same  as  for  track  c.u 


A\005" 


(n)  100-Mil  Unilateral  Variable-Area  Comprex. — This  is  a  combination  of  two 
half-width  variable-area  tracks  which  may  be  scanned  by  the  same  equipment 
as  is  used  for  track  w.16 


(0}  200- Mil  Bilateral  Variable-Area  Comprex. — This  track  is  intended  for  the 
same  type  of  sound  system  as  tracks  m  and  n  but  utilizes  a  width  of  200  mils.16 


(p)  Three- Channel  Stereophonic  Comprex. — This  arrangement  consists  of  three 
100-mil  bilateral  variable-area  sound-tracks,  one  for  each  of  three  stereophonic 
channels,  and  a  fourth  100-mil  bilateral  variable-area  track  on  which  are  recorded 
the  compression  and  expansion  controls  for  all  three  channels.16- 17- 18 


Aug.,  1943]      RECENT  DEVELOPMENTS  IN  SOUND-TRACKS 


133 


THREE .080"SIGNAL  TRACK 


/— 325"--/oNE.080"CONTROL  TRACK' 


(q)  100^  Mil  Variable-Density — 5- Mil  Control. — This  consists  of  a  single  vari- 
able-density track  having  the  dimensions  of  a  standard  100-mil  release-print 
track,  with  the  addition  of  a  5-mil-wide  control-track  located  in  the  black  region 
between  sound-track  and  picture.  In  practice  the  control-track  is  variable- 
density,  frequency-modulated.  The  control-track  does  not  interfere  with  the 
playing  of  a  film  of  this  type  on  a  reproducer  not  equipped  for  control-track  re- 
production.19 


ONE  SIGNAL  TRACK 


:243"TO  <t  OF  SIGNAL  TRACK 

7          ( 


ONE  .005    CONTROL  TRACK 


(r)  100-mil  Variable-Area — Sprocket- Hole  Control-Track. — This  consists  of  a 
standard  100-mil  variable-area  track  plus  a  variable-area  control-track  approxi- 
mately 100  mils  wide  located  in  the  sprocket-hole  area.  The  width  of  the  control- 
track  determines  the  volume  change  and  may  also  be  used  for  switching  loud 
speakers.20 


MAXIMUM 


AIOOV 


134 


E.  M.  HONAN  AND  C.  R.  KEITH 


tf.  S.  M.  P.  E. 


(5)  Three- Channel  Stereophonic  Control-Track. — In  this  case  three  22-mil  stereo- 
phonic sound-tracks  occupy  the  space  normally  required  for  a  single  100-mil 
track.  A  5-mil  control-track  in  the  same  position  as  in  track  q  records  control 
signals  for  each  of  the  three  sound-tracks.  The  sound-tracks  and  control-track 
are  all  variable-density,  the  control-track  being  frequency-modulated.19 


THREE.022"SIGNAL  TRACKS 


.005 


ONE.005  CONTROL  TRACK 


(0  Three-channel — " Fantasound." — This  arrangement  employs  four  200-mil 
variable-area  push-pull  tracks,  three  being  used  for  sound  while  the  fourth  carries 
signals  for  controlling  the  sound  volume  in  various  loud  speakers.21 


THREE .I65"SIGNAL  TRACKS 


REFERENCES 

(All  references  are  to  J.  Soc.  Mot.  Pict.  Eng.,  except  the  first} 

1  Tech.  Bull.,  Research  Council,  Acad.  Mot.  Pict.  Arts  &  Sci.,  "Standard  No- 
menclature for  Release-Print  Sound-Tracks"  (Nov.  24,  1937). 

2  DEFOREST,  L.:   (May,  1923),  p.  61. 

»  MACKENZIE,  D.:    XII  (Sept.,  1928),  p.  730. 
*  MILLER,  W.  C.:    XV  (July.  1930),  p.  53. 


Aug.,  1943]      RECENT  DEVELOPMENTS  IN  SOUND-TRACKS  135 

CRANE,  G.  R.:  XXXI  (Nov.,  1938),  p.  531. 

FRAYNE,  J.  G.,  AND  SILENT,  H.  C. :  XXXI  (July,  1938),  p.  46. 

WENTE,  E.  C.:    XII  (Sept.,  1928),  p.  657. 

MARVIN,  H.  B.:    XII  (Apr.,  1928),  p.  86. 

MAURER,  J.  A.:    XIV  (June,  1930),  p.  636. 

10  KREUZER,  B. :   XIV  (June,  1931),  p.  671. 

11  DIMMICK,  G.  L.,  AND  BELAR,  H. :  XXIII  (July,  1934),  p.  48. 

12  SACHTLEBEN,  L.  T. :  XXV  (Aug.,  1935),  p.  175. 

13  DIMMICK,  G.  L.:  XXIX  (Sept.,  1937),  p.  258. 

14  CARTWRIGHT,  C.  H.,  AND  THOMPSON,  W.  S. :  XXXIII  (Sept.,  1939),  p.  289. 
16  LORANCE,  G.  T.,  AND  BENFER,  R.  W. :  XXXVI  (Apr.,  1941),  p.  331. 

16  SNOW,  W.  B.,  AND  SOFFEL,  A.  R. :  XXXVII  (Oct.,  1941),  p.  380. 
17.  FLETCHER,  H. :  XXXVII  (Oct.,  1941),  p.  331. 

18  WENTE,  E.  C.,  BIDDULPH,  R.,  ELMER,  L.  A.,  AND  ANDERSON,  A.  B.:  XXXVII 
(Oct.,  1941),  p.  353. 

19  FRAYNE,  J.  G.,  AND  HERRNFELD,  F.  P.:  XXXVIII  (Feb.,  1942),  p.  111. 

20  LEVINSON,  N.,  AND  GOLDSMITH,  L.  T.:  XXXVII  (Aug.,  1941),  p.  147. 

21  GARITY,  W.  E.,  AND  HAWKINS,  J.  N.  A. :  XXXVII  (Aug.,  1941),  p.  127. 


OPERATIONS  OF  ARMY  AIR  FORCE  COMBAT  CAMERA 
UNITS  IN  THE  THEATERS  OF  WAR* 


RALPH  JESTER** 


Summary. — The  Purpose  of  Army  Air  Forces  Combat  Camera  Units  is  to 
supply  tactical  and  operational  information  in  the  form  of  motion  picture  reports 
from  the  combat  zones.  This  is  a  specialized  activity  and  requires  specialized  train- 
ing and  organization. 

The  paper  describes  the  course  of  training  for  the  units  and  some  of  the  problems 
encountered  in  the  field. 


In  November  of  1942,  less  than  six  months  ago,  the  Army  Air 
Forces  sent  out  to  the  theaters  of  war  the  first  of  its  Combat  Camera 
Units.  These  units  had  been  activated  in  what  was  then  called  the 
Directorate  of  Photography,  Maps  and  Charts,  under  Colonel  Minton 
W.  Kaye,  to  fulfill  the  need  for  specialized  coverage  of  the  activities 
and  operations  of  the  Army  Air  Forces  overseas. 

The  purpose  of  these  units  is  to  supply  tactical  and  operational 
information  in  the  form  of  motion  picture  reports  from  the  combat 
zones.  They  are  instructed  to  photograph  the  conditions  under 
which  the  Air  Forces  are  operating  throughout  the  world,  to  cover 
combat  operations  both  on  the  ground  and  in  the  air,  to  secure 
photographic  and  recorded  statistical  information  from  pilots  and 
crew  members  returning  from  combat  and  reconnaissance  missions, 
record  photographically  the  handling  of  casualties,  battle  damage, 
new  and  unusual  methods  of  solving  maintenance  or  mechanical 
problems  in  the  field,  to  report  photographically  on  the  development 
of  bombing  patterns  and  on  the  altitude  and  intensity  of  anti-aircraft 
fire  over  specific  enemy  positions. 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  Major,  Headquarters   Chief,   Editorial  Section,    Motion   Picture   Branch, 
Army  Air  Forces,  Washington,  D.  C. 

136 


AlR  FORCE'COMBAT  CAMERA  UNITS  137 

The  assignment  is  pretty  broad  and  consequently  the  ideal  combat 
cameraman  must  function  with  the  dependable  efficiency  of  a  trained 
motion  picture  technician,  coupled  with  the  unscrupulous  inquisi- 
tiveness  and  obnoxious  tenacity  of  the  newsreel  man.  That  this 
latter  quality  is  certain  to  be  found  in  one  spot  at  least  is  evidenced 
by  the  fact  that  a  general  recently  returned  has  reported  that, 
"That  damned  cameraman  is  getting  in  everybody's  hair — but  I'm 
for  him!" 

This  presents  one  of  the  key  problems  of  the  photographic  coverage 
of  modern  war — how  these  highly  specialized  technicians  can  operate 
among  highly  specialized  technicians  of  another  sort  and  what 
supplementary  military  training  enables  them  to  do  so. 

From  the  beginning  of  the  war,  the  Germans  had  already  realized 
the  value  of  the  motion  picture  camera  in  a  conflict  of  global  propor- 
tions. They  saw  that  pictures  could  bring  the  field  of  battle  within 
view  of  all,  from  the  general  staff  to  the  lowest  trainees,  as  well  as 
within  view  of  the  people  at  home.  And,  moreover,  the  pageant  of 
victory  could  be  brought  to  the  people  who  were  to  be  intimidated 
by  documentary  evidence  of  German  prowess.  To  whatever  uses 
the  German  Army  may  be  putting  motion  pictures  now,  the  or- 
ganization for  it  was  developed  and  put  into  operation  as  far  ahead 
of  us  as  was  the  rest  of  their  war  machine. 

The  American  military  mind,  with  some  notable  exceptions,  was 
not  as  quick  to  grasp  the  potential  of  this  medium  for  reporting 
infinitely  varied  operations  on  an  intercontinental  scale.  Moreover, 
covering  the  operations  of  such  a  thing  as  an  Air  Force  presented 
special  problems  which,  incidentally,  are  only  now  beginning  to  be 
mastered. 

Such  mastery  is  necessarily  based  upon  the  development  and  care- 
ful integration  of  personnel  and  equipment,  together  with  trans- 
portation, processing,  and  dissemination. 

From  the  standpoint  of  personnel,  the  Air  Forces  leaned  toward 
the  policy  that  the  making  of  motion  pictures  is  a  highly  specialized 
activity  and  is  best  conducted  by  individuals  who  are  experienced  in 
its  processes.  Consequently,  men  were  sought  within  the  industry, 
with  emphasis  upon  actual  production  experience  in  the  newsreel, 
entertainment,  or  industrial  field.  The  chief  of  the  Motion  Picture 
Branch,  Technical  Service  Division,  AAF,  was  brought  from  the 
ranks  of  well  known  directors;  he  is  Lt.  Colonel  William  J.  Keighley. 

The  course  of  training  for  Combat  Camera  Crews  before  going 


138  R.  JESTER    '  [J.  s.  M.  P.  E. 

overseas  is  tough  and  thorough.  Due  to  the  fact  that  these  men 
operate  under  combat  conditions  and  form  part  of  the  regular  bomber 
crews  over  enemy  positions,  it  was  necessary  to  decide  upon  the 
advisability  of  making  a  machine-gunner  out  of  a  cameraman  or  a 
cameraman  out  of  a  machine-gunner.  It  was  concluded  that  a 
cameraman  is  the  end  product  of  a  great  deal  of  experience,  and  can 
not  be  turned  out  in  a  few  weeks. 

Consequently  the  entire  complement  of  each  unit  undergoes  a  com- 
plete course  of  military  training  which  includes,  among  many  other 
things,  flexible  gunnery.  As  you  may  know,  the  Air  Forces  training 
program  lays  particular  stress  upon  the  fact  that  a  bomber  crew  is  a 
team.  To  inject  into  this  closely  knit  group  a  man  who  is  along  for 
the  ride — "to  snap  pictures,"  as  the  other  members  might  think  of 
it — would  be  unwise.  It  is  letting  you  in  on  no  secret  problem  of 
morale  to  point  out  that  in  some  areas  this  was  at  one  time  a  factor. 
However,  if  the  pilot  and  his  crew  feel  that  the  cameraman  is  capable 
of  holding  up  his  end,  and  that  he  has  been  trained  to  know  what  to 
do  under  fire  and  can  drop  his  camera  for  a  gtm,  he  becomes  one  of 
the  crew — each  respecting  the  other  for  his  specialized  contribution. 
Once  in  the  air  they  all  share  the  same  risks. 

In  this  connection,  reports  have  come  from  the  front  that  three 
cameramen  have  been  officially  credited  with  enemy  planes.  Most 
recently,  Tech.  Sergeant  James  Bray  replaced  a  wounded  gunner 
and  shot  down  an  ME-109.  Lt.  Mogen,  cameraman,  was  less  for- 
tunate— he  failed  to  return  from  Attu. 

Each  unit  includes  several  cameramen,  a  sound  crew,  still  photog- 
raphers, drivers,  an  adjutant,  et  al.,  in  sufficient  numbers  to  allow 
detachments  to  cover  different  areas  and  missions  simultaneously. 
The  impression  should  not  be  had  that  all  the  enlisted  men  are  from 
Hollywood  or  the  newsreel  field.  This  is  more  nearly  true  of  the 
officer  personnel,  whereas  the  majority  of  the  enlisted  men  are  from 
the  field  of  commercial  photography  or  have  been  graduated  from 
the  Army  Air  Forces  Photographic  School  at  Lowry  Field,  Colorado. 

Nor  is  every  man  in  the  unit  on  flying  status.  Only  those  whose 
duties  require  them  to  engage  in  regular  flights  for  photographic 
purposes  and  have  passed  the  proper  physical  examination  are 
classified  as  air  crew  members,  along  with  the  radio  men,  gunners, 
and  engineering  crew.  Such  men  wear  the  crew  member  wing  in- 
signia if  they  have  had  fifty  hours  of  flying  duty  as  a  member  of  an 
aircrew,  or  have  participated  as  a  member  of  an  air  crew  in  an  opera- 


Aug.,  1943]  AIR  FORCE  COMBAT  CAMERA  UNITS  139 

tional  combat  mission  during  which  exposure  to  enemy  fire  was  prob- 
able and  expected,  or  have  been  physically  incapacitated  for  further 
duty  as  a  member  of  an  air  crew  while  a  member  of  such  a  crew  be- 
cause he  was  wounded  as  a  result  of  enemy  action  or  injured  while 
discharging  the  duties  of  an  air  crew  member. 

Motion  picture  photography  from  an  airplane  presents  many  and 
special  difficulties  that  have  long  challenged  cameramen,  engineers, 
and  designers  of  equipment.  Photographing  another  airplane  or 
group  of  planes  or  a  ground  objective  from  another  swift-moving 
plane  is  a  difficult  job  with  complex  problems  involving  such  factors 
as  vibration,  the  slip-stream,  obstructions  to  vision,  and  temperature. 
This  is  further  complicated  by  the  fact  that  the  plane  is  primarily  a 
military  weapon  and  the  film,  except  for  reconnaissance,  can  not 
strictly  be  considered  such.  The  cameraman  does  not  shoot  to  kill; 
he  shoots  to  preserve.  As  a  result,  his  position  in  the  plane  receives  a 
priority  after  that  of  the  gunner,  who  must  have  the  greatest  range 
of  vision  for  the  field  he  is  to  cover.  Various  ingenious  approaches 
have  been  made  to  this  problem,  even  to  cutting  a  window  in  the 
leading  edge  of  the  vertical  stabilizer  supporting  the  rudder.  Mounts 
have  been  developed  to  photograph  through  the  floor  and  all  other 
available  openings  that  will  not  conflict  with  the  functions  of  the 
aircraft;  in  some  instances  the  cameras  are  motor-driven  and  re- 
motely controlled  by  a  member  of  the  crew.  Shooting  through  the 
plexiglass  of  the  nose  is  good  for  certain  types  of  planes  and  subject 
matter,  with  or  without  a  fixed  mount.  Hand-held  cameras  are, 
of  course,  most  flexible;  but  produce  pretty  jumpy  results  in  atmos- 
pheric turbulence  or  where  bumpiness  is  produced  by  anti-aircraft 
fire. 

The  units  have  been  provided  with  the  best  equipment  available; 
but  in  the  early  stages,  at  least,  this  did  not  always  mean  a  great 
deal,  because  little  or  nothing  was  available.  Of  necessity  the  equip- 
ment is  heterogeneous. 

I  am  not  at  liberty  to  tell  you  the  exact  numbers  of  either  men  or 
cameras;  but  there  is,  roughly,  a  camera  for  each  man  in  the  unit. 
Single-system  sound  cameras  are  provided  each  unit — Audio  Akeleys, 
Wahls,  or  Mitchells.  Each  has  several  silent  motion  picture  cameras, 
either  Bell  &  Howell  or  Akeley,  and  several  motor-driven  Eyemos 
with  400-ft  magazines.  The  most  numerous  types  are  the  hand- 
held cameras — Eyemo,  Cineflex,  DeVry,  Filmo,  and  Victor.  For 
still  cameras  there  are  two  speed  Graphics. 


140  R.  JESTER 

As  mentioned  above,  one  of  the  photographic  objectives  of  bomb- 
ing missions  is  to  provide  a  film  report  on  the  development  of  bomb- 
ing patterns,  and  to  record  the  altitude  and  density  of  flak.  In  some 
areas  this  is  done  at  extremely  high  altitudes,  with  resultant  compli- 
cations due  to  low  temperatures.  Men  have  risked  their  lives  in  the 
performance  of  a  job  at  which  they  were  licked  before  they  started. 
One  of  our  men  was  downed  in  Crete,  later  crash-landed  in  the 
Mediterranean  and  lost  his  camera,  finally  got  over  Naples,  at  last 
had  a  shot  at  his  objective,  and  had  his  camera  freeze. 

As  a  result  of  such  discouragements,  the  building  of  a  special 
camera  was  undertaken,  a  camera  that  would  not  be  affected  by  the 
extremes  of  temperature  encountered  in  the  shooting  of  motion 
pictures  from  planes.  Tests  on  one  camera  being  built  for  the  Air 
Force  to  meet  these  extremes  have  proved  that  this  is  possible,  and 
it  has  functioned  perfectly  at  65  degrees  below  zero. 

On  this  planet,  at  least,  it  is  impossible  to  expose  film  under  more 
varied  light  and  atmospheric  conditions  than  are  being  encountered 
by  our  combat  camera  units.  From  Persia  to  Guadalcanal,  from  the 
Aleutians  to  Burma,  men  are  filming  Air  Force  operations  under  an 
infinite  variety  of  handicaps.  One  crew  reports  twelve  consecutive 
missions  over  Kiska,  with  increasing  Japanese  anti-aircraft  fire,  and 
never  a  hole  through  the  mist  to  get  a  shot.  Others  are  nursing  raw- 
stock  through  the  tropical  moisture  of  New  Guinea  and  watching  for 
Jap  snipers. 

If  it  is  your  custom,  out  of  courtesy,  to  accord  these  papers  some 
measure  of  applause,  may  I  be  allowed  to  endorse  mine  over  to  the 
men  of  the  combat  camera  crews  throughout  the  world  who  are  faced 
with  as  tough  a  photographic  assignment  as  has  ever  had  to  be  put 
on  film. 


DEVELOPMENTS  IN  THE  USE  OF  MOTION  PICTURES 
BY  THE  NAVY* 

WILLIAM  EXXON,  JR.** 

Summary. — Naval  training  films  are  based  upon  a  complete  and  continuous 
integration  of  requirements,  planning,  production,  and  utilization.  This  is  in 
order  to  provide  maximum  effectiveness  for  audio-visual  aids.  The  conditions  of 
final  utilization  tend  to  govern  the  treatment,  the  reducing  or  eliminating  the  need 
for  any  superfluous  content. 

Since  my  last  address  to  this  Society,  the  Navy's  use  of  motion 
picture  films  has  been  developing  extensively  and  by  geometric  pro- 
gression. Those  of  you  who  are  in  the  business  of  manufacturing 
and  distributing  16-mm  motion  picture  projector  equipment  may 
have  some  inkling  of  the  incredibly  large  number  of  projectors  we 
are  attempting  to  acquire. 

Those  of  you  who  are  connected  with  certain  motion  picture  pro- 
ducing organizations  will  have  some  conception  of  the  vast  range  in 
the  number  of  productions  which  we  are  initiating.  Those  of  you 
who  are  connected  with  the  provision  of  film  stock  and  with  develop- 
ing and  printing  laboratories  will  have  an  idea  of  the  enormous 
amount  of  footage  we  consume.  I  am  not  permitted  to  give  you 
exact  figures  in  any  of  these  categories,  but  I  believe  it  is  fair  to  state 
that  the  actual  figures  would  probably  seem  surprisingly  high. 

The  daily  mails  bring  in  numerous  requests  for  films.  Every  day 
we  receive  dozens  of  requests  for  specific  titles.  Some  of  the  in- 
dividual requests  list  hundreds  of  titles.  The  Navy's  motion  picture 
film  catalogue,  which  is  not  available  to  the  public,  is  half  an  inch 
thick  and  contains  several  thousand  items  of  film  and  film-strip. 
The  Navy  makes  use  of  films  from  many  sources.  Some  we  derive 
from  our  Allies,  some  from  commercial  sources,  and  others  from  the 
Army  and  Coast  Guard.  The  Marine  Corps  produces  films,  some  of 
which  are  valuable  for  other  Naval  purposes.  Our  major  source, 
however,  is  production  for  and  by  the  Navy  itself. 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  Lt.  Commander,  U.S.N.R.,  Bureau  of  Navigation,  Navy  Dept.,  Washington, 
D.  C. 

141 


142  W.  EXTON,  JR.  tf.  s.  M.  P.  E 

As  a  general  rule  film  production  in  the  Navy  originates  with  a 
request  from  a  Naval  activity;  this  activity  may  be  one  of  the 
Bureaus  of  the  Navy  Department,  it  may  be  the  Commandant  of  a 
district,  or  it  may  be  the  Commanding  Officer  of  a  training  activity. 
Such  a  request  for  production  is  normally  addressed  to  the  Bureau 
of  Aeronautics  via  the  Bureau  of  Naval  Personnel.  It  therefore 
reaches  the  Bureau  of  Naval  Personnel  first;  and  is  there  subjected 
to  rather  careful  scrutiny.  A  survey  is  conducted  to  determine  all 
comparable  parallel  or  related  material,  in  order  that  duplication 
may  be  avoided  and  in  order  that  a  knowledge  may  be  had  of  every- 
thing of  the  kind  requested  that  may  already  be  in  existence.  It  is 
then  scrutinized  from  the  point  of  view  of  utilization ;  that  is  to  say, 
the  request  is  considered  with  expert  knowledge  of  the  places  where 
the  subject  is  taught,  the  conditions  under  which  it  is  taught,  the 
numbers  of  men,  and  the  sizes  of  the  groups  to  which  it  is  to  be 
taught.  Also  considered  would  be  the  relationship  to  other  things 
that  have  been  or  are  to  be  taught  to  the  same  men,  and  any  other 
matters  that  affect  the  eventual  utilization  of  the  finished  film. 
Naval  and  training  policy  and  doctrine  are  considered,  and  a  priority 
is  assigned  to  the  film  indicating  its  relative  importance.  Any  other 
suggestions  that  may  seem  germane  are  added,  and  all  this  is  in- 
corporated in  an  endorsement  accompanying  the  request  to  the  Bur- 
eau of  Aeronautics. 

The  Bureau  of  Naval  Personnel  may  also  conduct  an  extensive 
inquiry  into  the  needs  for  the  film,  the  concept  behind  it,  the  ex- 
tensive character  of  the  film  required;  whether  the  training  need 
could  be  served  as  well  by  film-strips  or  even  by  non-photographic 
training  aids,  such  as  wall  charts  or  models.  Provision  is  made  for 
the  designation  of  a  technical  advisor  who  will  provide  official  guid- 
ance in  the  Naval  aspects  of  the  film.  This  endorsement  accom- 
panying the  request  reaches  the  Bureau  of  Aeronautics,  where  the 
Training  Film  Unit  then  takes  the  matter  up.  This  unit  of  the 
Bureau  of  Aeronautics  is  charged  with  arrangements  for  actual  pro- 
duction, which  involves  the  selection  of  a  commercial  producer  or 
arrangements  with  the  Photo  Science  Laboratory.  The  project 
supervisor  and  an  educational  consultant  are  assigned,  and  these 
confer  with  the  technical  advisor.  The  production  is  then  under  way. 

In  many  cases,  the  film  in  its  preliminary  stages  is  referred  back 
to  the  Bureau  that  requested  it;  in  some  cases  in  the  form  of  a  script, 
and  in  other  cases  in  the  form  of  an  uncut  print  in  the  preliminary 


Aug.,  1943]        USE  OF  MOTION  PICTURES  BY  THE  NAVY  143 

stages  before  the  sound-track  is  added.  Usually,  the  technical  ad- 
visor is  present  at  such  a  preliminary  showing,  and  final  suggestions 
may  be  made  before  the  production  is  entirely  complete.  Experience 
has  shown  this  sort  of  final  review  to  be  very  desirable  in  many  cases. 
This  is  especially  so  in  training  films  that  apply  to  subjects  of  wide, 
general  application;  and  which  are  not  highly  technical,  and  there- 
fore of  limited  audiences. 

Two  of  the  newest  developments  in  the  Navy's  use  of  training  films 
are  involved  in  the  post-production  stage.  They  have  to  do  with 
the  Navy's  present  practices  in  connection  with  distribution  and 
utilization.  The  present  distribution  procedure  is  to  set  up  allow- 
ance lists  of  training  film  for  each  naval  activity;  that  is  to  say,  a  list 
of  the  individual  titles  that  each  activity  should  have  for  permanent 
possession,  as  being  particularly  appropriate  to  it.  In  addition,  a 
number  of  training-film  libraries  are  being  established  in  strategic 
places.  Each  of  these  libraries  is  thoroughly  equipped  with  films 
and  also  with  extra  projectors  and  equipment,  and  facilities  for 
projector  repair  and  film  renovation.  Through  these  film  libraries, 
films  are  available  for  loan  to  naval  activities  everywhere  upon 
request. 

Some  fifty  highly  qualified  educators,  with  special  experience  in 
the  field  of  using  audio-visual  training  materials,  have  been  com- 
missioned and  are  being  stationed  in  training  activities  where  their 
advice  and  guidance  in  the  use  of  training  films  and  other  training 
aids  are  now  resulting  in  the  derivation  of  maximum  benefit  from  the 
availability  of  this  material. 

In  attempting  to  be  brief,  I  have,  of  course,  eliminated  many 
details  that  are  important  and  interesting.  It  is  a  fact,  nevertheless, 
that  the  Navy's  use  of  motion  picture  films  today  is  absolutely  com- 
plete and  continuous  from  the  original  request  through  planning  and 
production  to  the  distribution  and  the  utilization  of  the  film.  All 
these  and  every  step  in  each  one  of  these  stages  are  a  part  of  a  con- 
tinuously planned  and  integrated  program  guaranteeing  maximum 
effectiveness  and  usefulness  of  each  film.  It  is  not  pretended  that 
every  step  in  the  development  and  use  of  each  film  is  a  perfect  one; 
nevertheless  it  is  believed  that  this  comprehensive  program  enables 
the  Navy  to  derive  benefits  from  the  use  of  films  in  training  that  are 
not  otherwise  available.  It  is  believed  that  the  Navy's  experience 
in  the  development  of  this  procedure  will  be  of  great  value  to  the 
future  of  educational  films. 


144  W.  EXXON,  JR.  [J.  s.  M.  P.  E. 

One  tendency  inherent  in  this  situation  is  to  get  still  further  away 
from  the  so-called  "Hollywood"  or  "entertainment"  technique  in 
educational  or  training  films.  A  film  is  not  required  to  sell  itself  by 
attempting  to  be  witty  or  amusing.  The  film  is  tied  into  a  training 
program  of  which  it  is  a  logical  and  important  part.  The  value 
derived  from  the  film,  therefore,  can  be  any  fraction  of  the  value 
that  has  been  put  into  the  film,  depending  upon  the  skill  with  which 
the  educational  program  is  conducted.  Comparatively  few  films 
now  being  produced  by  the  Navy  department  rely  upon  interest- 
arousing  or  interest-exciting  superfluousness.  On  the  other  hand, 
the  films  are  not  shown  indiscriminately,  and  therefore  the  audiences 
seeing  them  know  that  there  is  a  purpose  in  seeing  them.  They  are 
properly  prepared  for  seeing  these  films,  and  the  whole  situation 
surrounding  the  showing  of  the  film  is  such  as  to  arouse  in  them  a 
recognition  of  the  necessity  for  deriving  from  the  film  all  that  is 
possible. 

An  example  of  this  is  the  Night  Lookout  Training  Program.  The 
Navy  has  erected  a  number  of  Night  Lookout  Training  Centers 
provided  with  stages  simulating  night  conditions  and  equipped  with 
ship  models  of  varous  types;  and  with  lighting  systems  permitting 
the  simulation  of  dawn,  dusk,  distant  gun  fire,  and  so  forth.  A  com- 
petent lecturer  utilizes  this  equipment  to  demonstrate  the  principles 
of  being  a  good  lookout  at  night  and  of  using  the  eyes  properly  at 
night.  In  this  connection  night  or  dark  adaptation  and  the  physiol- 
ogy of  the  eye  become  matters  of  great  interest.  A  film  that  has 
been  produced  for  the  Navy,  and  which  illustrates  the  physiology  of 
night  vision  is  shown  in  order  to  assist  in  understanding  this  subject. 
The  film  is  technical  and  contains  no  entertainment  matter  what- 
ever; and  yet  under  the  conditions  in  which  it  is  shown,  it  is  re- 
garded as  extremely  successful  in  producing  the  desired  effect  by  de- 
livering the  desired  information. 

Many  of  the  simpler  aspects  of  utilization  require  attention  that 
is  not  often  given  them.  Such  simple  and  obvious  matters  as  proper 
projection  and  proper  seating  in  relation  to  the  screen,  so  that  mini- 
mum satisfactory  vision  is  obtained,  are  matters  that  may  require 
guidance.  The  fact  that  the  average  man  can  not  continue  to  derive 
benefit  from  seeing  instructional  film  for  a  prolonged  period  is  a  fact 
that  needs  to  be  driven  home.  Our  utilization  experts  insist  that 
not  more  than  ten  to  fifteen  minutes  of  instructional  film  be  shown  at 
any  one  time,  and  this  should  generally  be  preceded  by  introductory 


Aug.,  1943]        USE  OF  MOTION  PICTURES  BY  THE  NAVY  145 

remarks  and  be  followed  by  remarks  from  the  instructor  that  will 
tend  to  drive  home  what  should  have  been  learned  from  the  film. 

Other  functions  of  the  utilization  officer  include  advising  those  con- 
ducting training  activities  as  to  the  kinds  of  film  and  other  materials 
that  are  available  for  their  special  purposes.  This  involves  far  more 
extensive  activity  than  can  readily  be  imagined  by  anyone  who  is  not 
familiar  with  the  vast  range  of  naval  training  activities,  including  at 
present  many  hundreds  of  different  establishments. 

If  any  of  you  could  sit  at  certain  desks  at  the  Navy  department, 
and  hear  the  telephone  ring,  and  answer  telephone  calls  from  high 
ranking  officers  attached  to  important  ships  of  war,  demanding  pro- 
jectors and  films  for  those  ships  on  an  urgent  basis,  you  would  realize 
that  the  fighting  Navy  is  convinced  of  the  value  of  training  films. 
That  value,  to  the  Navy,  is  increasingly  based  upon  an  intelligent  and 
comprehensive  conception  of  the  kinds  of  film  desired,  their  appli- 
cation to  the  subject,  and  the  conditions  and  circumstances  under 
which  the  subject  will  be  taught. 


PROBLEMS  IN  THE  PRODUCTION  OF  U.  S.  NAVY 
TRAINING  FILMS* 


ORVILLE  GOLDNER** 


Summary. — The  organization  of  the  Training  Film  Branch  and  the  scope  of  its 
job  are  indicated.  Problems  encountered  in  the  production  of  the  Navy's  training 
films  are  considered.  Special  emphasis  is  given  to  research,  pre-planning  of  pro- 
duction and  script  writing.  The  difficulties  that  result  from  undertaking  an  extensive 
training-film  production  program  under  wartime  conditions  are  presented  briefly. 

Slide-films  and  motion  pictures  for  the  Navy  are  being  produced 
under  the  supervision  of  the  Chief  of  the  Bureau  of  Aeronautics,  who 
was  directed  by  the  Secretary  of  the  Navy,  in  August,  1941,  to 
"...  fulfill  the  photographic  requirements  of  education  and  training 
in  the  naval  service."  The  Photographic  Board,  which  made  the 
original  recommendation  on  which  the  Secretary  acted,  lumped  the 
responsibility  for  the  photographic  requirements  of  education  and 
training  with  other  photographic  responsibilities  and  assigned  them 
all  to  the  Bureau  of  Aeronautics  because  of  its  long-time  experience 
in  naval  photography. 

As  a  result  of  this  directive,  the  Photographic  Division  of  the 
Bureau  of  Aeronautics,  through  its  Training  Film  Branch,  serves  the 
entire  Navy  in  its  film  production  program.  Requests  for  film 
productions  originate  from  training  officers  in  the  various  naval 
training  centers  maintained  throughout  the  country,  or  from  officers 
in  the  training  divisions  in  Washington.  Requests  come  to  the 
Bureau  of  Aeronautics  via  the  Bureau  of  Naval  Personnel,  which  has 
responsibility  for  all  naval  training.  There  are,  however,  two  ex- 
ceptions to  this.  They  are  the  requests  that  originate  in  aeronautical 
activities  and  those  that  originate  in  the  Secretary's  office.  These 
requests  come  to  the  Chief  of  the  Bureau  of  Aeronautics  and  are 
forwarded  to  the  Training  Film  Branch  via  the  Director  of  Photog- 
raphy. 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  Lt.,   U.S.N.,   Training  Film   Branch,   Photographic    Division,    Bureau   of 
Aeronautics,  Navy  Dept.,  Washington,  D.  C. 

146 


U.  S.  NAVY  TRAINING  FILMS  147 

When  production  requests  are  approved  by  the  cognizant  authori- 
ties, the  Training  Film  Branch  assigns  a  two-man  team  to  work  with 
the  technical  advisor  in  outlining  and  producing  a  training  film  on 
the  subject.  One  team  member  is  the  educational  consultant,  the 
other  the  project  supervisor.  Essentially,  the  project  supervisor  is 
the  coordinator  and  administrator  of  the  project  for  the  Navy. 
Besides  contributing  the  film  ''know  how,"  he  activates  the  project 
through  his  liaison  relationships  with  the  several  persons  jointly 
engaged  in  it — the  technical  advisor,  the  Navy  or  commercial  pro- 
ducer, the  educational  consultant,  the  procurement  and  cataloguing 
departments  of  the  Training  Film  Branch. 

The  educational  consultant  helps  to  insure  that  a  film,  as  planned, 
teaches.  He  not  only  defines  a  film's  purpose  but  helps  to  plan  it 
according  to  well  established  pedagogical  principles.  He  finds  ways 
to  fit  it  into  existing  curricula  and  may  assist  in  adapting  existing 
curricula  to  the  new  instructional  program.  In  several  instances  it 
has  been  found  that  pictures  have  forced  realignment  of  existing 
curricula. 

Since  the  organization  of  the  Branch  charged  with  responsibility 
for  producing  films  for  the  Navy  (July,  1941),  the  total  number  of 
projects  completed  is  1692.  Of  these,  1412  were  slide-films  and  280 
were  motion  pictures.  The  total  number  of  projects  in  production 
at  this  time  is  1296,  of  which  850  are  slide-films  and  446  are  motion 
pictures.  Requests  for  production  of  films  on  additional  subjects  of 
interest  to  Navy  training  are  coming  in  at  the  rate  of  200  a  month — 
clear  evidence  of  the  Navy's  interest  in  the  medium. 

Another  line  of  evidence  showing  the  Navy's  dependence  upon 
training  films  is  found  in  the  film  distribution  figures.  In  the  last 
quarter,  over  90,000  prints  have  been  distributed.  Nearly  one 
thousand  individual  activities  have  been  served.  These  include  both 
ships  and  the  nearly  five  hundred  schools  and  naval  training  estab- 
lishments ashore  where  men  are  trained  before  being  assigned  to  the 
fleet  or  to  which  they  are  returned  for  further  training  after  some 
fleet  experience. 

The  training  films  the  Navy  makes  and  uses  have  been  designed 
to  be  used  in  classrooms  at  the  time  in  the  course  when  they  will  help 
the  instructor  to  standardize  operations  and  make  ideas  clear  to  his 
students.  They  are  not  made  to  be  shown  as  separate,  uncorrelated 
features.  And  when  planned  for  one  specific  group,  as  is  most  often 
the  case,  they  are  not  expected  to  meet  the  complete  needs  of  another 


148  O.  GOLDNER  [J.  S.  M.  P.  E. 

group  being  taught  things  in  a  different  way.  For  example,  slide- 
films  designed  for  use  in  the  Aviation  Service  Schools  for  training 
enlisted  men  in  maintenance  and  repair  of  airplanes  have  not  been 
found  particularly  helpful  for  training  civilian  personnel  in  the 
Aviation  Assembly  and  Repair  Shops,  even  though  both  groups  are 
working  on  the  same  model  of  airplane.  The  films  the  latter  need 
are  definitely  job-analysis  films  on  assembly  and  sub-assembly  of 
parts,  much  too  detailed  to  be  of  use  in  the  Service  Schools.  The 
purposes  served  in  each  are  different,  and  hence  the  training  aids 
must  of  necessity  be  different  too.* 

It  is  our  task  continuously  to  analyze  the  problems  peculiar  to  and 
characteristic  of  every  training  situation.  Training  films  must  fit. 
Simply,  they  must  assist  in  training  or  they  are  an  expensive  waste  of 
time  and  strategic  material. 

We  find  it  necessary  to  repeat  frequently  that  we  are  not  in  the 
business  of  making  films  per  se;  we  are  in  the  business  of  making 
training  aids.  That  is  why  in  a  training  film  program  like  the 
Navy's  there  is  no  place  for  the  movie  making  prima  donna.  Cellu- 
loid fever  is  easy  to  get,  but  the  making  of  effective  training  materials 
requires  analytical,  straight-line  thinking,  planning,  and  execution. 

When  an  official  request  reaches  the  Training  Film  Section,  there 
are  still  a  great  many  questions  that  have  to  be  answered  before  a 
producer  can  be  assigned  to  the  task  of  producing  the  training  film. 
A  thorough  job  of  research  and  pre-planning  must  be  done.  Due  to 
the  problems  inherent  in  a  training  program  during  a  war  period, 
basic  research  and  pre-planning  take  on  various  aspects.  First, 
there  is  the  research  based  upon  standardized  doctrine,  good  or  bad, 
realistic  or  unrealistic,  which  has  been  used  over  a  long  period  of  time 
by  a  fairly  well  stabilized  training  activity.  Second,  there  is  the 
research  on  a  training  program  where  there  is  no  established  doctrine  — 
where  the  whole  training  program  is  so  new  that  a  syllabus  or  simple 
outline  has  not  been  developed. 

Frequently  it  becomes  the  job  of  the  Training  Film  Branch  to 
establish  the  doctrine  along  with  the  production  of  the  training  film. 
In  many  cases,  a  training  activity  without  established  doctrine  per- 
mits the  creation  of  a  more  effective  training  film  than  the  activity 

*  The  foregoing  was  written  by  Lt.  Reginald  Bell,  U.S.N.R.,  Senior  Educational 
Officer  for  the  Training  Film  Branch.  It  is  reproduced  here  substantially  as  it 
appeared  in  Visual  Review  for  1943.  The  remainder  of  the  paper  was  written 
by  Lt.  Orville  Goldner,  U.S.N.R.,  Officer  in  Charge,  Training  Film  Branch. 


Aug.,  1943]  U.  S.  NAVY  TRAINING  FILMS  149 

that  presumably  has  all  its  information  frozen  in  outmoded  hand- 
books and  syllabi.  It  is  far  more  stimulating  for  the  project  super- 
visor, the  educational  consultant,  and  the  technical  adviser  to  ap- 
proach a  problem  that  has  not  been  thoroughly  explored.  A  training 
film  that  evolves  out  of  such  a  situation  is  almost  certain  to  be  more 
operational  and  less  abstract  than  one  that  has  been  built  out  of  a 
maze  of  words  and  formulas. 

If  no  technical  adviser  is  indicated  on  a  .request  when  it  arrives 
at  the  Training  Film  Branch,  it  is  obvious  that  the  Branch  must 
insist  upon  the  appointment  of  a  technical  adviser  before  the  basic 
research  on  the  training  film  project  can  begin.  It  is  always  hoped 
that  the  technical  adviser  will  come  to  the  Training  Film  Branch 
with  two  basic  qualifications — first,  that  he  will  be  a  subject-matter 
specialist,  thoroughly  experienced  in  the  technical  aspects  of  the 
proposed  training  film;  second,  that  he  have  sufficient  authority 
to  make  decisions  that  will  hold  and  be  approved  by  his  bureau  or 
the  activity  which  he  represents.  If  the  technical  adviser  happens 
to  be  a  desk  engineer  with  years  of  experience  or  a  technical  writer 
who  has  thought  in  terms  of  words  and  mathematics  entirely  when 
considering  his  subject,  he  almost  invariably  creates  many  difficulties 
for  all  those  concerned  in  the  production  of  the  training  film. 

Let  us  consider  for  a  moment  the  first  type  of  research — that 
based  almost  exclusively  upon  doctrine  set  forth  in  great  detail  in 
handbooks  and  manuals.  If  the  subject  happens  to  be  mechanics 
or  electricity  or  any  one  of  a  hundred  other  involved  subjects  on  the 
complicated  apparatus  of  this  war,  in  all  probability,  the  authors  of 
the  manuals  and  handbooks  were  engineers  sitting  at  the  desks  of 
the  manufacturer  of  the  equipment  involved.  It  has  been  the 
practice  of  the  armed  services  for  many  years  to  buy  with  their  equip- 
ment instructional  manuals  that  are  supposed  to  contain  the  sum 
and  substance  of  all  the  problems  involved  in  the  construction,  in- 
stallation, maintenance,  and  repair  of  the  equipment.  Frequently 
these  have  been  considered  all  that  is  necessary  for  the  guidance  and 
training  of  competent  personnel.  Needless  to  say,  these  handbooks 
and  manuals  are  generally  one-sided — they  tell  the  story  about  the 
equipment  that  the  manufacturer  wants  to  tell.  Constructed  as 
they  are,  in  Detroit,  Chicago,  Cleveland,  or  other  industrial  centers, 
miles  from  the  field  of  operation  in  which  the  equipment  is  used,  they 
are  unrealistic,  verbose,  and  crammed  with  mathematics  that  only 
thoroughly  experienced  engineers  can  understand.  And  yet  more 


150  O.  GOLDNER  [J.  S.  M.  P.  E. 

than  once,  these  engine  encyclopedia,  Diesel  dictionaries,  and  radio 
rhetorics  have  been  given  to  training  film  officers  as  scenarios. 
"Certainly,"  says  the  technical  adviser,  "what  more  do  you  want?" 
"Just  make  pictures  to  fit,  and  you'll  have  a  beautiful  training 
film."  And,  believe  it  or  not,  we've  made  a  few  along  this  line — 
abstract  talking  panoramas  to  delight  the  eyes  and  ears  of  our  best 
engine  Einsteins. 

We  have  been  speaking  here  of  one  kind  of  material  that  is  pre- 
sented as  doctrine  for  the  construction  of  training  films.  This  is  the 
overcomplicated  and  unrealistic  which  makes  picture  planning 
difficult.  Another  kind  of  material  presented  as  doctrine  is  the 
oversimplified — that  kind  that  grew  up  in  an  unstudied  training 
program,  in  the  hands  of  an  alleged  instructor  who  thought  that 
generalizations  were  enough.  This  kind  of  material  contains  pro- 
found statements  such  as  "Proceed  to  the  engine,  make  adjustments 
preparatory  to  starting,  turn  up  fuel  oil  to  the  proper  level,  turn 
throttle  to  recommended  starting  position,  proceed  as  recommended 
in  Section  C,  p.  32  of  the  Manufacturer's  manual,  serial  number  836, 
etc.,  etc." 

We  who  are  involved  in  the  construction  of  training  aids  for  the 
Navy  know  that  neither  of  these  kinds  of  material  is  sufficient  as  a 
basis  or  plan  for  an  effective  training  film.  Our  job  of  basic  research 
must  go  further.  Consider  for  a  moment  the  construction  of  train- 
ing films  on  a  series  of  large  tactical  problems  which  change  from 
day  to  day  just  as  the  war  itself  changes  from  day  to  day.  The 
movement,  the  pattern  of  strategy,  the  war  equipment  that  won  a 
battle  yesterday  may  not  win  the  battle  at  some  future  date  for  which 
we  are  building,  and  yet,  we  have  to  make  training  films  on  these 
problems  too.  One  such  problem  has  kept  us  involved  for  over  a 
year.  In  that  time,  tactics  have  changed,  equipment  has  changed, 
and  personnel  has  changed.  Technical  advisers  who  were  considered 
authorities  when  we  began  may  no  longer  be  considered  authorities, 
or  they  have  been  removed  to  fields  of  operation  inaccessible  to  the 
Training  Film  Branch,  for  every  day,  more  men  must  go  to  combat 
areas  whether  they  are  working  on  training  films  or  not.  It  is  safe 
to  say  that  within  the  year,  typewritten  material  a  foot  thick  has 
been  accumulated  on  this  particular  problem.  Dozens  of  experts 
have  been  consulted  and  countless  maneuvers  have  been  watched 
for  the  purpose  of  accumulating  authentic,  operational  data.  There 
must  be  continuous  checking  and  cross-checking — for  an  error,  made 


Aug.,  1943]  U.  S.  NAVY  TRAINING  FILMS  151 

real  and  in  effect  true  by  projection  on  the  screen  of  the  classroom, 
could  conceivably  lose  a  battle  if  enough  people  believed  it  and 
acted  accordingly.  Conversely,  the  truth  projected  and  made  real — 
simply  and  operationally — might  win  the  battle.  It  is  this  admitted 
effectiveness  that  justifies  the  production  of  training  films;  in  fact, 
demands  it. 

Such  a  job  of  research  and  analysis  is  not  .an  easy  task.  It  is 
difficult  enough  to  get  a  consensus  on  problems  where  standard 
mechanisms  are  involved.  It  is  overwhelmingly  difficult  to  get  a 
consensus  when  broad  tactical  problems  and  intricate  new  machines 
of  war  are  involved.  Often,  much  valuable  time  is  lost  in  getting  a 
decision  on  a  simple  point,  and  these  delays  are  not  easy  to  overcome 
or  explain;  for  in  the  end,  there  is  the  project  file  in  the  Training 
Film  Branch  which  indicates  that  a  certain  training  film  has  been  in 
production  an  inordinately  long  period  of  time.  With  a  few  projects 
like  this,  the  total  production  program  is  bound  to  look  out  of  joint. 
But  the  research,  pre-planning,  checking,  and  cross-checking  must 
be  done. 

The  second  research  technique — that  which  is  without  benefit  of 
doctrine  to  begin  with — is  largely  observational.  The  project  super- 
visor, educational  consultant,  and  technical  adviser  travel  to  the 
training  activity  that  is  to  furnish  the  problem  and  the  pattern  for 
the  training  film.  A  typical  example  would  be  the  assembly  of  a 
pontoon  bridge.  Let  us  assume  that  this  is  a  new  activity  for  the 
Navy,  that  the  pontoons  are  new,  that  the  total  job  is  a  part  of  an 
entirely  new  operation  which  extends  the  function  of  an  established 
Navy  rating.  On  such  a  problem,  the  researchers  scrutinize  what 
is  going  on.  This  may  take  a  couple  of  days  or  a  couple  of  weeks  or 
longer.  It  may  mean  a  trip  to  the  South  Pacific  or  the  Caribbean, 
to  one  location  or  many  locations.  But  inevitably,  it  means  a  de- 
tailed analysis  of  work  under  many  conditions.  With  the  training 
officer  in  charge,  project  personnel  attempt  to  determine  what  tools 
are  best  and  what  techniques  are  best  for  the  job  to  be  done,  wherever 
and  however  it  must  be  done.  The  training  film  must,  of  necessity, 
set  high  standards  for  this  particular  operation  wherever  it  is  shown. 
Perhaps  the  training  officer  had  never  thought  of  his  job  in  terms  of 
the  best  tools  and  best  techniques;  perhaps  it  had  been  done  pre- 
viously with  whatever  tools  were  at  hand  by  whatever  method 
seemed  most  appropriate  at  the  moment.  Obviously,  this  is  not 
precise  enough  for  the  discerning  eye  of  the  camera.  When  a  simple 


152  O.  GOLDNER  [J.  S.  M.  P.  E. 

wrench  in  use  is  projected  on  the  screen,  it  may  appear  at  once  to 
be  either  too  large  or  too  small,  or  badly  handled.  Unskilled  and 
indecisive  workmanship  and  inappropriate  equipment  becomes  read- 
ily apparent  when  reviewed  on  the  single  plane  of  the  classroom 
screen.  A  recent  example  of  this  happened  in  a  series  of  films  being 
undertaken  by  the  Branch  on  the  disassembly  of  a  certain  engine. 
The  two  Machinist's  Mates  assigned  to  appear  in  the  films  were 
thought  to  be  thoroughly  qualified  for  the  job.  Aboard  ship  in  the 
engine  room,  they  could  undoubtedly  get  by  as  able  mechanics.  And 
yet,  when  the  first  sequences  of  the  particular  training  film  were  pro- 
jected, it  became  apparent  immediately  that  these  two  men  were 
inept  with  tools  and  frequently  used  methods  that  could  not  be  con- 
sidered as  standards  for  the  training  film.  The  sequences  were  re- 
shot  and  the  films  continued  with  more  experienced  mechanics  who 
knew  the  proper  tools  and  techniques.  All  this  points  to  the  fact 
that  research  and  pre-planning  can  not  be  casual  if  effective  training 
aids  are  to  result,  and  further  that  the  production  of  training  aids 
must  not  be  considered  as  a  manufacturing  process  in  which  one 
film  formula  is  the  skeleton  over  which  a  wide  variety  of  subject 
matter  can  be  stretched.  Whenever  this  happens,  the  formula 
becomes  more  important  in  a  teaching  situation  than  the  subject 
matter  it  purports  to  present.  Training  films  designed  on  this 
pattern  are  inevitably  soporific  and  can  not  help  but  defeat  the 
purpose  for  which  they  are  intended. 

What  does  the  Training  Film  Branch  do  after  the  research  and  pre- 
planning on  a  given  project  are  considered  finished  and  approved  to 
a  point  where  production  may  be  started  with  safety  ?  A  qualified  pro- 
ducer must  be  selected.  Scripts  must  be  written;  a  location  or 
locations  must  be  prepared.  Personnel  and  material  must  be 
allocated.  These  and  a  myriad  of  other  jobs  are  next  in  line. 

And  all  this  must  be  accomplished  in  some  order  while  the  Navy 
and  the  nation  are  at  war.  All  this  must  be  done  without  stopping 
the  flow  of  men  and  equipment  to  the  battle  front,  without  taking  too 
much  of  the  valuable  time  of  technical  advisers  who  are  at  the  same 
time  preparing  themselves  and  others  for  actual  contact  with  the 
enemy.  All  this,  like  research,  is  not  easy.  Every  step  of  the  way 
is  fraught  with  problems.  There  is  always  the  problem  of  priority. 
Who  shall  be  first  and  what  project?  When  everything  is  needed 
now  and  urgency  is  the  order  of  the  day,  there  still  must  be  some 
plan — something  first  and  something  second — when  the  time  of 


Aug.,  1943]  U.  S.  NAVY  TRAINING  FILMS  153 

leaders  and  the  allocation  of  facilities  are  considered.  Then  there 
is  the  problem  of  security.  The  Navy's  equipment  and  plans  have 
to  be  protected  vigilantly  day  and  night,  for  the  enemy  is  ever  pres- 
ent and  alert.  How  is  it  done?  Many  of  you  are  producers  work- 
ing for  the  Navy  and  you  know.  It  is  sufficient  to  say  that  it  is 
done,  slowly,  continuously,  meticulously.  It  is  tedious  and  time- 
consuming  for  you  and  for  us,  but  when  the  safety  of  the  nation  is  at 
stake,  it  is  only  wisdom  to  be  hyper-cautious. 

Let  us  examine  critically  some  of  the  steps  in  actual  production. 
What  of  script  writing?  It  should  not  be  necessary  to  labor  the 
point  that  a  training  film  is  not  like  a  theatrical  film  and  not  for  the 
same  purpose,  and  not  for  an  audience  with  the  same  mental  set. 
Neither  is  a  training  film  like  a  newsreel  which  cuts  quickly  from 
subject  to  subject  accompanied  by  a  commentary  which  on  analysis 
says  nothing  but  says  it  well  and  with  so  much  seeming  authority. 
Each  type  of  film  has  its  place  in  our  culture,  but  one  can  not  be  sub- 
stituted for  the  other  in  a  training  situation.  Yet,  many  of  the 
writers  of  the  Navy's  training  films  are  hard  to  convince  of  this  fact. 

The  writing  of  a  script  for  an  effective  training  film  requires  first 
of  all  the  ability  to  penetrate  the  obvious  and  the  loosely  accepted 
truths  in  a  given  situation.  It  requires  persistence  and  a  prying 
curiosity.  It  requires  incisiveness  and  straight-line  thinking,  and 
with  it  all,  the  ability  to  put  it  on  paper  in  acceptable  English  with 
an  economy  of  words.  The  writer  of  a  training  film  script  must,  of 
necessity,  have  a  vivid  imagination.  He  must  be  picture-minded 
first  and  word-minded  second.  In  analyzing  his  subject  matter,  he 
must  ask  himself  constantly,  "What  is  the  picture  at  this  point  that 
will  tell  the  story  in  terms  of  the  objective?"  And,  having  deter- 
mined the  picture,  he  must  then  ask,  "What  is  the  simplest  mean- 
ingful statement  that  I  can  make  that  will  extend  the  effectiveness 
of  the  picture  and  add  to  its  retention  potentiality?"  The  writer 
with  genuine  ability  for  training  film  production  understands  that 
he  is  working  with  a  medium  in  which  the  primary  value  is  visual 
and  the  secondary  value  is  auditory.  He  knows  that  he  is  not  writ- 
ing lectures  with  pictures  "to  fit" ;  he  is  organizing  pertinent  pictures 
of  subject  matter  in  movement,  using  the  fewest  possible  words  to 
describe,  to  emphasize,  to  extend. 

Does  the  Training  Film  Branch  get  what  it  wants  in  the  way  of 
scripts  for  its  films?  Frequently  it  does,  but  time  after  time  it  does 
not.  There  is  much  revising,  much  compromising,  and  occasionally 


154  O.  GOLDNER  [J.  S.  M.  P.  E. 

the  accepting  of  the  obviously  bad  in  the  name  of  urgency.  Gener- 
ally, no  one  can  be  blamed  for  the  inadequacies.  Perhaps,  in  spite 
of  all  research,  sufficient  data  were  not  available  to  give  continuity 
to  the  picture  plan.  Perhaps  certain  pictures  were  known  to  be  un- 
obtainable and  without  them  the  plan  would  have  blind  spots. 
Then  again,  perhaps,  there  had  been  insufficient  experience  with  a 
given  piece  of  equipment  to  furnish  the  facts  about  a  certain  opera- 
tion. 

However,  there  are  times  when  script  shortcomings  stand  out  as 
direct  evidence  of  the  writer's  refusal  to  accept  the  training  film  as  a 
special  instrument  with  a  special  purpose.  When  writers  insist  upon 
using  pictorial  cliches  at  the  beginnings  and  ends  of  all  training  films, 
it  becomes  obvious  that  they  do  not  know  how  to  begin  and  how  to 
end  the  film  in  terms  of  the  objective  originally  set  forth.  It  points 
to  a  limited  concept  of  the  job  to  be  done  and  a  definite  lack  of 
ability  to  work  in  the  film  medium.  Words  can  not  describe  the 
fatigue  that  comes  from  going  to  the  projection  room  and  seeing  film 
after  film  begin  and  end  with  the  opticals  made  up  of  the  same 
twenty-five  best  stock  shots  of  ships  plowing  through  the  waves,  big 
guns  shooting  at  nothing,  and  planes  peeling  off,  accompanied  by 
ominous  words  in  sepulchral  tones  on  the  scope  of  the  war  and  the 
size  of  the  job  and  the  beauties  of  Democracy  and  the  beating  we  are 
going  to  give  Hirohito,  etc.,  etc.  And  we  must  not  forget,  indeed, 
can  not  forget,  the  overloud,  strident  music  that  fits  the  film  the  way 
ice  cream  goes  with  dill  pickles. 

The  writer  may  not  wish  to  take  credit  ior  all  this,  but  he  sets  the 
pattern — good  or  bad — and  the  director,  the  cameraman,  the  editor, 
cutter,  and  narrator  all  follow  the  line. 

Photography  itself  is  probably  the  least  of  our  problems.  Most 
cameramen  are  able  to  get  some  kind  of  image  on  the  film.  Inas- 
much as  a  large  part  of  the  shooting  of  training  films  must  go  on  in 
spite  of  weather  conditions  and  countless  other  limitations,  it  is 
generally  necessary  to  accept  photography  that  is  adequate,  rather 
than  good.  To  insist  upon  photography  that  is  the  best  possible 
under  ideal  conditions  in  a  given  situation  would  often  delay  projects 
beyond  reasonable  limits. 

Producers  who  work  on  training  films  for  the  Navy  are  always  con- 
scious of  the  demands  for  close-ups,  for  better  definition,  and  maxi- 
mum depth  of  field.  These  are  essential  in  operational  training  films. 
Of  great  importance  also  are  the  orientation  and  re-orientation  shots 


Aug.,  1943]  U.  S.  NAVY  TRAINING  FILMS  155 

for  which  the  Training  Film  Branch  asks  over  and  over  again.  A 
training  film  that  skips  around  over  an  engine  or  a  ship  or  anything 
else  with  close-ups  and  medium  close-ups  is  certain  to  lose  and  con- 
fuse the  trainee.  He  must  be  orientated  to  the  problem  in  the  be- 
ginning, and  must  be  re-orientated  at  intervals  throughout  the  film. 
This  orientation  must  be  operational;  that  is,  it  must  be  from  a 
position  in  which  the  trainee  would  find  himself  if  lie  were  working 
with  the  real  thing  in  a  tactile  relationship.  Frequently,  effective 
orientation  shots  are  not  possible  in  live  photography,  and  it  becomes 
necessary  to  resort  to  diagrams  or  other  pictorial  devices.  Any  de- 
vice is  legitimate  if  it  achieves  the  purpose  for  which  it  is  intended. 
Here  again,  like  all  the  other  complicated  aspects  of  training  film 
production,  the  photography  is  right  when  it  gets  to  the  screen  the 
cogent  picture  information  that  the  training  situation  demands. 

It  is  not  necessary  to  have  beautiful  clouds  in  all  exterior  shots 
and  to  have  every  Diesel  mechanic  backlighted  in  close-ups  to  make 
him  glamorous,  but  realistic  esthetics  have  a  place  in  training  films. 
The  cameraman  who  understands  his  medium,  who  uses  his  camera 
creatively  and  not  like  a  garden  hose,  can  combine  on  the  screen  the 
document  of  an  activity  in  a  composition  of  values  from  white  to 
black  that  adds  immeasurably  to  the  value  of  the  film  and  the  pleas- 
ure of  the  audience. 

Considerable  time  could  be  spent  on  other  subjects  as  they  relate 
to  the  production  of  training  films.  These  include  music,  color, 
animation,  sound  effects,  narrators — their  voice  quality  and  de- 
livery— and  the  subtle  but  emphatic  values  of  the  great  range  of 
screen  devices.  There  are  others,  but  they  are  beyond  the  scope 
of  this  paper. 

In  conclusion,  it  seems  necessary  to  say  a  few  words  about  the  job 
that  confronts  us  jointly — you,  as  civilian  motion  picture  engineers, 
technicians,  and  producers,  and  those  of  us  in  the  armed  services  as 
technicians  and  educators  working  on  the  production  of  training 
films. 

We  have  a  war  to  win.  There  is  much  to  be  done  before  we  win  it 
and  bring  it  to  a  victorious  climax.  Every  effort  we  make  must  be 
to  that  end.  Each  has  a  job  to  do,  and  ours  is  training  men  to  be 
more  effective,  with  less  danger  to  themselves,  in  some  phase  of  this 
intricate  bloody  struggle.  One  of  the  media  we  are  using  for  this 
training  job  is  the  motion  picture. 

How  can  you  help  more  ? 


156  O.  GOLDNER 

By  studying  with  us  the  bottlenecks  that  are  keeping  all  of  us 
from  being  as  effective  as  we  should  be.  There  are  the  bottlenecks 
in  animation,  in  laboratory  work,  and  in  optical  work.  You  can 
help  by  analyzing  the  facilities,  the  equipment,  and  the  processes 
involved.  Certainly,  there  are  ways  to  improve  all  three.  There 
must  be  ways  to  turn  out  more  of  a  better  product,  faster. 

We  can  look  at  the  work  being  accomplished  for  the  armed  serv- 
ices by  all  the  facilities  of  the  motion  picture  industry  with  con- 
siderable satisfaction.  But,  in  terms  of  the  job  to  be  done,  we  must 
look  to  the  future  with  an  expanding  concept  of  the  function  of  the 
motion  picture  and  a  more  profound  understanding  of  its  value  as 
a  training  instrument. 


THE  16-MM  COMMERCIAL  FILM  LABORATORY' 

WM.  H.  OFFENHAUSER,  JR.  ** 


Summary. — Several  years  ago  J.  A.  Maurer  reported1  upon  the  graininess  of 
direct  16-mm  prints  in  comparison  with  reduction  prints  from  35-mm  negatives. 
Somewhat  earlier'2'  he  reported  upon  the  status  of  direct  16-mm  sound  in  comparison 
with  sound  optically  reduced  from  35-mm  to  16-mm.  The  comparisons  appeared 
so  favorable  to  16-mm  that  the  next  step  was  to  put  the  procedures  into  commercial 
use.  This  paper  describes  the  methods  and  the  machinery  used  for  the  purpose. 

It  was  necessary  to  standardize  laboratory  and  film-handling;  all  picture  printers 
are  of  the  slow-speed  step-contact  type,, all  use  the  same  type  of  lamp  as  a  light-source. 
All  sound  printers  are  of  the  optical  type;  all  use  the  same  type  of  lamp  and  the 
same  type  of  ammeter  for  control.  No  contact  sound  printing  whatever  is  used,  due 
to  the  very  serious  losses  that  result  from  such  printing. 

It  was  found  that  one — and  only  one — raw-film  material  should  be  used  for  each 
operation — the  material  with  the  best  resolving  power.  Fortunately  the  material 
with  the  best  resolving  power  has  the  other  necessary  desirable  photographic  charac- 
teristics. Eastman  5203  was  selected  as  the  duplicate  negative  material.  Dupont 
605  was  chosen  for  the  release  print  raw  stock;  Agfa  250  for  the  original  sound 
negative  material.  Kodachrome  was  found  to  be  the  best  available  material  for 
original  16-mm  films,  not  only  for  color  duplicates  but  also  for  black-and-white 
fine-grain  release  prints  as  well. 

It  was  necessary  also  to  standardize  inspection  equipment,  especially  sound 
equipment.  A  film-phonograph  of  excellent  film  motion  with  a  0.4-mil  slit  image, 
a  noise-free  amplifier,  and  a  two-way  loud  speaker  system  of  the  horn  and  direct- 
radiator  type,  with  a  standard  400-cycle  cross-over  network,  is  used  for  the  inspection 
of  16-mm  sound  negatives  and  sound  prints  that  are  used  for  further  duplicating 
(for  example,  prints  used  for  Kodachrome  duplicating).  The  overall  electrical 
characteristic  of  the  system  is  similar  to  that  of  metal  diaphragm  systems  specified 
in  the  "Revised  Standard  Electrical  Characteristics  for  Two-Way  Reproducing 
Systems  in  Theaters"  issued  in  1938  by  the  Academy  of  Motion  Picture  Arts  & 
Sciences.  For  combined  print  inspection,  Bell  &  Howell  utility  projectors  adapted 
to  connect  into  the  system  used  for  the  film-phonograph  were  found  the  best  commercial 
compromise. 

Uniformity  of  product  is  readily  obtained;  permanent  records  of  each  piece  of 
film  processed  are  sufficiently  complete  to  permit  the  duplication  of  results  long  after 
the  details  of  a  particular  job  are  forgotten.  With  but  one  variable  in  each  significant 
step  of  the  process,  errors  in  processing  are  quickly  traced  and  corrected.  Maximum 

*  Presented  at  the  1942  Fall  Meeting  at  New  York,  N.  Y. ;   received  March 
15,  1943. 

**  Precision  Film  Laboratories,  Inc.,  New  York,  N.  Y. 

157 


158  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  P.  E. 

uniformity  is  achieved  simultaneously  with  maximum  output;  the  methods  described 
are  well  suited  10  mass  production. 

In  discussing  the  16-mm  motion  picture  film  laboratory  and  its 
commercial  operation  and  practices  we  shall  ignore  in  this  paper  time- 
consuming  and  attention-diverting  frills  such  as  fades,  wipes,  dis- 
solves, and  whirls,  and  concentrate  entirely  upon  the  operation  of  a 
laboratory  in  relation  to  the  thought  content  and  purpose  of  the 
films  to  be  produced.  In  war  nothing  can  be  condoned — much  less 
encouraged — that  does  not  directly  contribute  to  the  accomplish- 
ment of  the  desired  purpose. 

What  is  the  primary  purpose*  of  a  16-mm  film  laboratory,  or  for 
that  matter,  of  our  16-mm  industry,  now  that  we  have  been  engaged 
in  war  for  the  larger  part  of  a  year?  No  one  who  is  familiar  with  the 
facts  can  honestly  include  pure  and  simple  entertainment  and  blatant 
advertising;  there  is  but  one  real  objective:  training  and  its  related 
films  dedicated  to  the  job  of  making  training  of  ever-increasing  scope 
available  to  an  ever-expanding  group  of  our  trained  citizens,  and  to 
make  our  methods  more  effective  from  the  standpoint  of  saving  time 
and  improving  the  quality  of  instruction. 

At  the  Fall  Meeting  of  the  Society  three  years  ago  at  New  York, 
this  identical  statement  was  made  in  an  appeal  for  the  production  of 
business  films  for  internal  use;3  in  today's  language,  training  films. 
The  fundamental  requirements  of  a  good  training  film  program  now, 
as  then,  remain  essentially  the  same  as  reported  by  the  Luchaire 
Committee  on  Intellectual  Cooperation  of  the  League  of  Nations  in 
1924: 

(1)  Slides  and  motion  pictures  should  be  used  for  maximum 
effectiveness.     As  a  general  rule,  the  use  of  these  two  adjuncts  is 
not  judicously  proportioned,  one  often  being  used  to  the  complete 
exclusion  of  the  other.     We  can  no  doubt  agree  that  the  conclusion 
of  eighteen  years  ago  is  still  valid  today;  too  many  projects  use  but 
one  medium  to  the  complete  exclusion  of  the  other. 

(2)  All  objects  and  scenes  that  the  audience  is  intended  to  watch 
and  remember  in  movement  should  be  shown  in  movement.     Still 
pictures  representing  objects  and  scenes  that  ought  to  be  seen  in 
movement  should  be  banned,  as  giving  a  distorted  impression  of  the 
actual  facts.     Our  films  are  much  improved  in  this  regard  although 
we  still  find  instances  where  stationary  objects  are  photographed 

*  This  paper  does  not  take  into  account  the  16-mm  prints  of  entertainment 
films  furnished  by  Hollywood  to  the  Armed  Forces. 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  159 

with  a  motion  picture  camera  and  moving  objects  with  a  still  camera. 

(3)  The  screen  can  not  displace  the  personal  element;    it  can  to 
some  extent  displace  printed  matter,  and  it  should,  in  all  events,  be 
used  in  combination  with  it.     The  use  of  the  screen  in  conjunction 
with  text-books  and  printed  matter  is  still  quite  undeveloped;    its 
effectiveness  when  properly  used  is  in  the  top  rank  of  communication 
media.     "Nuts  and  bolts"  pictures  especially  can  take  advantage 
of  this  pedagogically  correct  instructional  technique. 

(4)  The  screen  should  be  used  in  combination  with  personal  con- 
tact in  "getting  the  idea  across."     It  should  be  used  at  the  location 
where  the  teacher  ordinarily  operates  whenever  it  is  of  advantage  to 
do  so.     It  should  be  possible  to  repeat  the  picture  several  times  if 
necessary;    the  picture  should  be  definitely  constructed  in  such  a 
manner  that  it  will  bear  repetition.     A  really  well  made  film  can  be 
run  at  least  five  or  six  times  before  it  begins  to  seem  dull. 

Training  practice  has  shown  a  tendency  to  bring  the  screen  to  the 
student  instead  of  the  student  to  the  screen.  This  tendency  is  in  the 
proper  direction  and,  fortunately,  is  steadily  growing. 

It  is  not  true,  however,  that  films  are  always  constructed  in  such  a 
manner  as  to  bear  repetition,  as  is  particularly  necessary  in  films  for 
instructional  purposes.  Too  often  a  large  number  of  diverting 
technical  effects  such  as  fancy  wipes,  dissolves,  and  the  like  have 
been  used  in  a  single  reel.  Such  technical  effects  do  not  cover  up  the 
glaring  defects  in  plot,  continuity,  and  lack  of  logical  presentation 
that  are  also  usually  present.  Our  technical  effects  wherever  used 
shall  aid  the  story,  not  "steal  the  show." 

(5)  The  screen  can  not  be  used  in  the  proper  manner  unless  there 
is  very  wide  distribution  of  effective  up-to-date  apparatus  so  that 
each  teacher,  of  even  small  classes,  can  have  his  own  projection  equip- 
ment.    The  simplest  apparatus  to  handle  consistent  with  complete 
technical  adequacy  will  be  best.     If  the  screen  is  to  do  its  proper 
work,  the  apparatus  must  quickly  become  a  thing  in  daily  use. 

On  the  whole,  current  commercial  16-mm  sound  projectors  (and 
this  includes  those  being  currently  purchased  by  the  Government  in 
quantity  under  the  most  strict  specifications),  while  quite  satisfactory 
in  most  particulars,  almost  invariably  have  the  following  inadequate 
or  poorly  designed  features  : 

(a)  The  Loud  Speaker.* — Present  flat  baffle  types  are  hopelessly  inadequate 
for  high-quality  reproduction.  For  semipermanent  installations  an  efficient 
horn-and-cone  combination  such  as  the  Jensen  speaker,  supplied  under  the 


160  W.  H.  OFFENHAUSER,  JR.  [J.  S.  M.  P.  E. 

Bell  &  Howell  trade-name  "Orchestricon,"  is  quite  suitable.  For  semiportable 
use,  a  reflex -type  horn  of  reasonable  efficiency  and  frequency  characteristic  such 
as  the  Jensen  "Hypex"  is  quite  suitable.  The  loud  speaker  should  be  designed 
to  cover  with  sound  the  area  to  be  served  by  picture. 

(6)  Sound  Optics. — Present  machines  (except  only  the  Eastman  Kodak) 
use  sound  optics  of  inferior  resolving  power  providing  very  coarse  projected  slit 
images;  a  width  of  not  greater  than  0.5  mil  is  necessary  for  good-quality  16-mm 
sound  reproduction.  On  the  best  of  other  machines,  the  slit  width  is  twice  as 
wide  as  that  recommended,  1.0  mil. 

(c)  2-Inch  Picture  Projection  Lenses.6 — About  70  to  80  per  cent  of  the  pro- 
jectors in  use  should  use  a  projection  lens  of  this  focal  length;   unfortunately  all 
lenses  of  this  focal  length  of  wide  aperture  (//1. 6)  made  without  field  flatteners 
have  very  poor  resolution  in  the  corners  and  very  bad  field  curvature.     Only 
one  manufacturer  (Eastman  Kodak)  regularly  supplies  all  2-inch  lenses  with  a 
field  flattener.     The  field  curvature  and  poor  resolution  in  the  corners  still  persist 
in  2-inch  lenses  of  smaller  aperture  although  in  some  cases  not  to  as  great  a 
degree.     U.  S.  Army  and  other  Government  specifications  have  sought  to  get 
around  this  problem  by  specifying  lenses  of  3 -inch  focal  length  which,  at  smaller 
apertures,  show  less  field  curvature.     While  there  is  an  improvement  in  flatness, 
the  focal  length  is  definitely  wrong  for  the  average  application  as  judged  by  the 
criteria  of  the  Non-Theatrical  Committee  Report  of  July,  1941  ;6  the  projected 
image  is  too  small  and  the  perspective  incorrect. 

(d)  No  Provision  for  Proper  Focusing  of  "Non-Standard"  Emulsion  Position 
Prints.1 — Most   projectors   have  no   provision   whatever   for  refocusing   sound 
optics  for  Kodachrome  duplicates.     This  results  in  tubby,  noisy,  and  unintelli- 
gible reproduction  from  even  excellent  films.        Eastman  Kodak  is  the  only 
manufacturer  that  provides  sound  refocusing  as  standard  equipment  on  any 
standard  projectors;    Bell  &  Howell  provides  this  feature  as  optional  equipment 
at  extra  cost.     Since  there  is  almost  a  10  to  1  cost  ratio  between  cheap  black- 
and-white  prints  and  good  -Kodachrome  duplicates,  it  seems  an  anomaly  to 
provide  the  better  reproduction  for  the  cheaper  film.     No  manufacturer  makes 
any  provision  for  adjustable  pre-set  stops  for  refocusing  picture  of  Kodachrome 
duplicates  when  changing  from  standard  to  non-standard-position  films. 

(e)  Lack  of  Accessibility  for  Proper   Cleaning. — This  is  a  most  important 
feature,  universally  recognized  in  35-mm  theatrical  equipment  and  universally 
ignored  in  16-mm  projectors.     In  particular,  there  is  not  one  widely  distributed 
sound  projector  on  the  16-mm  projector  market  that  has  a  readily  removable 
and  properly  cleanable  picture  gate,  although  practically  every  35-mm  projector 
made  in  the  last  20  or  more  years  has  had  this  feature. 

(6)  The  mode  of  use  of  the  screen  must  be  improved,  having 
regard  to  the  fact  that  it  can  act  upon  the  mind  of  the  spectator 

(a)     By  faithful  presentation  of  the  subject. 

(6)     By  the  representation  of  the  subject  simplified. 

(c)  By  the  representation  of  the  subject  in  sections. 

(d)  By  the  representation  of  the  subject  intensified,  magnified,  speeded  up, 
slowed  down,  built  up  by  degrees,  or  superposed. 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  161 

These  different  methods  must  be  employed  according  to  a  logical 
scheme,  taking  into  account  the  subject  to  be  dealt  with  and  the 
specific  character  of  the  audience  to  which  the  film  is  planned  to  be 
shown. 

For  training  films  it  is  of  utmost  importance  that  the  exhibition 
and  use  plans  for  a  film  be  fully  completed  before  the  first  camera 
exposes  the  first  foot  of  film.  Maximum  effectiveness  presumes  the 
gearing  of  the  subject  matter  of  the  film  to  the  audience. 

(7)  The  screen  is  a  valuable  means  of  suggestion;   it  will  be  used 
as  a  time-saver,  often  a  valuable  one,  in  putting  across  all  matters 
that  depend  largely  upon  visual  memory. 

The  lighted  screen  in  the  darkened  room  compels  concentration 
upon  the  material  presented.  It  is  not  only  possible  to  put  across 
details  of  mechanisms  and  their  operation,  but  also  to  explain  the 
coordination  of  activities  that  can  not  in  the  usual  course  of  events 
be  directly  observed.  This  field  is  potentially  a  very  productive  one 
for  industry  as  well  as  for  our  Armed  Services. 

(8)  In  order  to  economize  effort  and  to  save  expense  in  making 
films,  and  to  derive  maximum  profit  from  them,  it  is  advisable  to 
decide  definitely  beforehand  to  what  extent  regular  photographing 
and  animation  are,  respectively,  to  be  used.     Due  to  the  high  cost  of 
animation  in  comparison  with  regular  photographing,  animation  has 
been  used  to  a  much  smaller  degree  than  in  many  cases  seems  de- 
sirable for  maximum  effectiveness;    however,  films  made  in  the  last 
year  have  shown  a  definite  improvement. 

THE  THREE-YEAR  INTERVAL  FOR  THE  16-MM  COMMERCIAL  LABORATORY 

The  16-mm  commercial  film  laboratory  has  "cleared  decks"  in  the 
past  three  years;  in  order  to  make  way  for  a  large  volume  of  high- 
quality  prints  in  Kodachrome  and  fine-grain  black-and-white  film  it 
has  eliminated  all  extraneou,s  activities.  It  no  longer  prints  35-mm 
Kodachrome  or  black-and-white  slide-films;  it  develops  no  35-mm 
film  and  makes  no  35-mm  prints  whatever.  The  precious  production 
capacity  formerly  taken  up  by  this  variety  of  activities  is  now  de- 
voted entirely  to  16-mm  high-quality  print  production.  Needless  to 
say,  this  action  has  made  it  possible  to  increase  greatly  the  output 
per  man-hour  and  per  dollar,  and  with  a  material  improvement  in 
technical  quality.  In  the  case  of  Precision  Film  Laboratories,  it  is 
possible  to  take  any  production  print  and  project  it  with  theatrical 
satisfaction  with  a  technically  complete  arc  projector  upon  a  12-ft 


162  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  P.  E. 

screen;  not  only  the  sound  but  also  the  picture  will  be  of  theatrical 
quality.  And  it  should  be  so;  the  inherent  resolution  of  today's 
best  materials  with  proper  handling  is  entirely  adequate  by  present- 
day  standards. 

PRESENT-DAY  16-MM  FILMS 

The  majority  of  16-mm  films  processed  today  in  the  16-mm  com- 
mercial laboratory  are  of  the  training  or  educational  type  which  are 
taken  silent  and  use  an  "off-stage  voice"  or  commentary  sound-track 
rather  than  synchronized  sound.  Since  we  are  a  nation  at  war, 
large  numbers  of  prints  are  needed  from  each  subject — and  simplicity 
and  speed  are  the  keynotes  in  the  production  of  these  direct  and 
to-the-point  films. 

The  Original  Picture  Film. — Sixteen-mm  originals  are  usually 
direct  positives;  either  black-and-white  reversal  or  Kodachrome. 
These  direct  positive  materials  are  almost  ideal  for  the  job  at  hand. 
The  dirt  and  scratches  usually  accumulated  in  usual  careful  handling 
are  quite  objectionable  when  negative  is  used  as  the  original  ma- 
terial. In  direct  positives,  however,  these  imperfections  are  prac- 
tically invisible  and  splices  do  not  show.  The  intermediate  negative 
and  print  (for  black-and-white)  permit  an  almost  infinite  number  of 
high-grade  black-and-white  prints  that  are  not  only  appreciably 
superior  to  35-mm  optical  reductions  as  to  graininess,  but  also  far 
better  as  to  softness  and  gradation  due  to  the  use  of  the  negative- 
positive  process  in  obtaining  the  final  result.  The  advantages  of 
direct  positive  materials  are  now  so  pronounced  that  negative-type 
materials  have  been  practically  eliminated  in  all  applications  where 
a  large  number  of  copies  is  required. 

Direct  positive  materials  are  not  ordinarily  developed  by  com- 
mercial film  laboratories;  since  the  cost  of  developing  is  included  in 
the  price  paid  for  the  film,  developing  is  under  control  of  the  film 
manufacturer.  This  applies  to  reversal  materials  as  well  as  to 
Kodachrome.  Some  independent  laboratories  are  reversing  positive 
film  but  the  volume  of  this  class  of  work  at  the  present  time  is  not 
large. 

Materials. — There  are  two  kinds  of  original  Kodachrome  available, 
"Regular"  (which  is  intended  for  use  in  daylight)  and  Type  A  (which 
is  intended  for  use  in  artificial  light).  The  prime  difference  between 
the  two  is  that  if  both  are  projected  with  the  usual  high-efficiency 
tungsten  lamp,  the  color  will  appear  correct  as  seen  by  daylight  for 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  163 

the  Regular  film  and  as  seen  by  highly  overvolted  Photoflood  No.  1 
or  No.  2  lamps  for  the  Type  A.  Since  the  blue-sensitivity  and  the 
green-sensitivity  of  Type  A  are  higher  than  that  of  Regular,  while 
the  red-sensitivity  is  nearly  the  same,  it  is  easier  to  use  Type  A  with 
a  filter  in  daylight  than  to  use  Regular  with  a  filter  in  artificial  light, 
as  the  calculated  speed  of  the  Type  A  film  so  used  does  not  appre- 
ciably change  Another  advantage  of  Type  A  used  with  a  filter  in 
the  outdoors  is  that  the  film  is  not  subject  to  "haze  trouble"  caused 
by  excessive  ultraviolet  and  blue- violet.  With  proper  color-tem- 
peratures, however,  it  is  best  to  use  Regular  for  daylight  and  Type  A 
for  artificial  light. 

Present-day  reversal  materials  still  give  the  impression  that  they 
are  intended  for  the  amateur  who,  according  to  a  current  fallacy, 
likes  his  film  as  fast  as  possible  and  as  "hard  as  nails."  In  original 
reversal  materials  today,  there  is  still  a  big  need  for  a  low-contrast, 
long-reproduction-scale  material,  since  there  is  no  such  material  on 
the  photographic  market  and  we  have  been  struggling  along  without 
it  for  some  five  years.  Agfa  did  manufacture  a  film  called  "Old  Type 
Superpan"  which  was  a  long-scale  material  of  beautifully  low  con- 
trast, but  it  was  unfortunately  withdrawn  from  the  market  when 
the  faster  emulsions  of  the  "Supreme"  type  made  their  appearance. 
The  film  manufacturer  who  supplies  such  material  and  incorporates  in 
it  the  new  emulsion  improvements  of  the  last  five  years  as  to  grain 
reduction  and  speed  will  not  only  earn  the  blessings  of  a  long-suffering 
professional  market  by  reopening  wide  fields  of  usefulness  but  also 
should  find  it  very  profitable  as  well.  All  finer-grained  reversal 
emulsions  available  today  are  of  the  high-contrast  type. 

Today's  Compromise. — Critical  professional  film  users  have  been 
aware  of  this  situation  for  the  past  two  years  or  more  and  have 
turned  to  Kodachrome  as  the  original  material  for  their  black-and- 
white  prints.  Kodachrome  has  appreciably  lower  contrast  than  any 
finer-grain  reversal  film  at  present  on  the  market,  and  in  the  opinion 
of  its  users,  is  well  worth  while  despite  its  higher  cost  and  lower  speed.* 
From  a  production  viewpoint  its  slower  speed  is  a  serious  handicap 
due  to  the  appreciably  larger  amount  of  lighting  equipment  necessary 
to  photograph  with  it.  It  must  be  remembered  that  the  mobility  of 
the  industrial  camera  is  measured  by  the  mobility  of  the  lighting 
equipment  required  to  illuminate  the  subject. 

*  See  Appendix  for  further  data. 


164  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  P.  E. 

The  Work  Copy. — The  first  step  in  handling  developed  direct 
positive  originals  is  to  make  the  usual  work-print  or  editing  copy. 
Basically,  there  is  little  here  to  describe  except  that  the  work-copy 
actually  made  depends  primarily  upon  the  functions  it  is  to  perform. 
It  may  vary  all  the  way  from  a  one-light  copy  made  on  positive 
stock  and  developed  in  a  positive  bath  (with  a  negative  viewing 
aspect)  to  a  Kodachrome  duplicate  intended  to  show  reasonably 
closely  the  color  balance  to  be  expected  in  the  release  duplicates. 

One  extremely  important  point  should  be  made :  while  it  is  true  that 
a  beautiful  photographic  copy  is  not  ordinarily  required  of  a  work- 
print,  it  is  equally  true  that  a  cheap  work-print  may  be  the  most 
costly  element  in  the  whole  production  process.  If  the  original  is 
scratched  by  careless  handling  or  by  printing  in  an  improperly  de- 
signed or  maintained  printer,  all  the  effort  made  to  obtain  an  other- 
wise excellent  original  is  futile.  Careless  handling  of  originals  during 
the  work-print  and  editing  stages  have  been  a  major  cause  for  what 
might  be  called  the  high  mortality  rate  of  otherwise  good  films. 

Both  work-print  and  original  picture  are  returned  to  the  film 
maker;  the  next  job  at  hand  is  the  editing  of  the  picture  and  the 
preparation  of  the  sound-track.  Generally  speaking,  the  commercial 
laboratory  does  not  edit  film,  as  its  function  is  to  perform  the  essen- 
tially mechanical  work  of  the  copying  process  without  attempting 
to  do  any  "creative"  work  whatever. 

The  Sound  Negative. — After  the  work-print  is  edited,  sound  is 
scored.  While  sound  is  recorded  as  a  negative  as  in  35-mm,  here 
again  the  procedure  diverges  widely.  Sound  is  recorded  upon 
yellow-dyed  high-resolving-power  film  exposed  through  a  blue 
filter;  ultraviolet  is  undesirable  as  it  causes  inferior  resolution.  The 
harmonic  distortion  with  an  85-per  cent  modulated  sound-track  of 
400  cycles  of  density  1.5  can  be  kept  as  low  as  1  per  cent;  with  ultra- 
violet light  and  usual  ultraviolet-type  film-stocks  in  the  same  ma- 
chine, it  is  difficult  to  get  the  distortion  down  to  6  per  cent.  The 
improvement  in  noise  level  of  yellow-dyed  film  is  likewise  satis- 
fyingly  large.  (Recently  blue-dyed  films  have  been  introduced 
whose  performance  characteristics  seem  to  be  quite  similar  to  those 
of  the  yellow-dyed  film  that  has  been  in  use  for  the  past  three  or  four 
years.) 

The  laboratory  develops  sound-film  at  standard  time  (which 
happens  to  be  6  minutes)  for  the  standard  negative  density  of  1.90. 
As  accurate  and  complete  control  is  essential  to  consistent  high- 


Aug.,  1943] 


COMMERCIAL  FILM  LABORATORY 


165 


Tape  To  Can  Which  This 
Log  Describes 

From 


SOUND  LOG  SHEET 
To 


Date:. 


Page  No.:.... 


PRECISION  FILM  LABORATORIES 


21  W.  46™  STREET 
N«w  YORK,  N.  Y. 


(Ctj  «•<»  Sute) 

Ordered  By 

Sound  Man 

Order  Number                    „       

Microphone  Man  

Title  of  Film.  

Location  :  

Cameraman  

,.  

Film:  Make:....  Emulsion  and  Coating  No.:  
B-M  Recorder  Type  No.:  Serial  No.:,..._.. 

Winding 
Lamp  No.:  

£*            Direction  £*  J 
Filter:..™  „._ 

B-M  AGN  Amplifier  Type  No.: Serial  No.: Current: 

B-M  Recorder  Amplifier  Type  No.: Serial  No.: Cum 

B-M  Power  Supply  Type  No.: .' Serial  No.: 

Microphone:  Name  and  Type: Setting:  R  —  D  —  C 


Decrease 


Filters:  Low  Pass  Type  No 


Serial  No.: . 


.Others: 


ST 

Take 
No. 

•&T 

Fs0r 

Scene 
Seconds 

cTent 

Mike 
Setting 

Main  Gain 
Setting 

o,SNon. 

REHAUU 

Exposure 
Test 


INSTRUCTIONS  TO  LABORATORY:  Develop  test  (last feet  on  outside  of  roll)  at  standard  time.   Develop  track  accordingly; 


INSTRUCTIONS  TO  LABORATORY:  Develop  test 

. .    ,.        ....  ,  ,     Black  and  White 

this  film  will  be  used  for  ^^ 

Test  Dev.  Time: Test  Density 

Please  fill  in  and  return  original  to _ 


Film  Dev.  Time: 


..Average  Density.™ „_.. 

, ;  retain  copy. 


FIG.  1.     Sound  log  sheet. 

quality  results,  all  information  transmitted  between  laboratory  and 
film-maker  is  in  writing.  A  typical  sound  log  sheet  is  shown  in  Fig. 
1.  Comparable  log  sheets  are  made  for  picture;  these  too  are  sent 
to  the  laboratory  to  give  the  laboratory  an  opportunity  to  suggest 
improvements  in  lighting  and  similar  matters  of  camera  technique. 

As  part  of  the  inspection  routine,  every  sound  negative  is  com- 
pletely run  and  inspected  at  synchronous  sound  speed  on  a  16-mm 
film-phonograph  and  reproducing  system  having  a  16-mm  frequency 


166  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  P.  E. 

response  characteristic  quite  like  that  of  the  Academy  of  Motion 
Picture  Arts  &  Sciences  standard  35-mm  characteristic  as  described 
in  the  Technical  Bulletin  of  October  10,  1938.  The  film-phonograph 
fulfills  the  requirements  of  such  standard  reproduction;  it  uses  an 
optical  system  with  an  0.4-mil  slit  produced  by  a  microscope  ob- 
jective together  with  an  8-volt,  2-ampere  exciter-lamp  to  provide  the 
necessary  mechanical  rigidity  of  the  filament  to  avoid  microphonic 
noise.  The  exciter-lamp,  together  with  the  heaters  of  amplifier 
tubes  operated  at  low  level,  is  energized  from  a  rectified  power-supply 
to  assure  satisfactorily  low  noise  and  hum  content.  The  amplifier 
drives  a  2- way  "horn-woofer"  loud  speaker  system  utilizing  a  con- 
ventional 400-cycle,  180-degree  cross-over  network.  Needless  to 
say,  the  combination  is  of  better  than  theatrical  quality,  as  is  neces- 
sary in  equipment  to  be  used  for  judging  sound  quality  critically. 

A  report  of  the  inspection  is  sent  to  the  customer,  and,  if  indicated, 
methods  of  correcting  difficulties  and  improving  quality  are  sug- 
gested. If  the  recording  is  below  par,  the  customer  is  advised  to 
make  a  retake.  Under  usual  conditions,  the  need  of  retakes  is  rare. 
It  is  interesting  to  note  that  distance  from  the  laboratory  is  no 
measure  of  the  quality  of  the  resultant  product ;  the  great  bulk  of  the 
exchange  of  information  is  arranged  by  mail ;  some  of  the  finest  work 
is  turned  out  by  film-makers  located  on  the  other  side  of  the  conti- 
nent as  well  as  by  those  within  a  stone's  throw  of  the  laboratory. 

The  Sound-Track  Print. — After  the  negative  has  been  approved,  a 
sound-track  print  is  made  for  checking  purposes.  This  is  in  every 
respect  the  highest-quality  sound-track  print  that  can  be  turned  out, 
as  the  quality  of  the  release  film  is  judged  by  this  print.  As  in  the 
case  of  all  other  16-mm  prints,  it  is  made  on  fine-grain  film.*  It  has 
been  found  impossible  to  make  good  sound-track  prints  with  a  con- 
tact printer;  accordingly,  all  sound  prints— both  combined  prints 
and  sound-track  prints — are  printed  on  a  one-to-one  optical  sound- 
printer  whose  slip  with  acetate  base  films  is  even  less  than  the  com- 
parable 35-mm  "slip"  of  high-grade  non-slip  printers  with  nitrate- 
base  films.  If  we  can  judge  by  the  papers  in  the  JOURNAL,  the  sound- 
track printers  for  Fantasia  were  of  the  general  type  used  for  16-mm; 
this  type  of  printer  had  been  in  use  for  16-mm  printing  for  several 
years  before  the  Fantasia  equipment  made  its  appearance. 

The  sound-track  is  then  projected  on  the  film-phonograph  equip- 

*  Technical  Appendix. 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  167 

ment  just  as  was  the  negative.  The  same  man  who  checked  the 
negative  usually  checks  the  print.  While  cases  of  defective  sound- 
prints  have  been  almost  unknown  for  the  last  year,  track-prints  are 
still  carefully  checked,  as  they  are  often  used  for  Kodachrome  dup- 
licating or  for  re-recording.  Fig.  2  is  a  typical  "pink"  sheet,  as  we 
call  our  Technical  Record  Sheet.  Fig.  3  shows  the  reverse  side  of 
the  "pink"  sheet;  as  will  be  noted,  very  little  is  left  to  the  imagina- 
tion when  defects  are  described. 

A  PRODUCTION  EXAMPLE 

Assume  that  the  job  to  be  done  is  making  Kodachrome  duplicates 
at  the  same  time  black-and-white  fine-grain  prints  are  to  be  made. 
The  film-maker  ships  to  the  laboratory  the  original  edited  Koda- 
chrome, his  Kodachrome  work-print,  the  sound  negative,  and  the 
sound-track  print.  These  are  accompanied  by  specific  instructions 
concerning  the  reproduction  required  in  key  scenes. 

Preparation. — The  film  is  turned  over  to  the  Preparation  Section, 
where  it  is  first  inventoried  and  then  prepared  for  printing.  This 
includes  checking  the  marking  and  identification  of  the  leaders  and 
the  inspection  of  splices  and  the  checking  of  emulsion  positions.  As 
this  work  is  the  function  of  the  film-maker  and  not  of  the  laboratory, 
the  film  is  returned  to  the  film-maker  for  correction  if  incomplete 
in  a  major  degree;  if  incomplete  in  a  minor  degree,  the  laboratory 
will,  upon  authorization,  perform  the  necessary  work.  In  the 
Preparation  Section,  the  timing  sheets  for  printing  are  made  ready — 
and  made  to  correspond  with  the  identification  leaders  on  the  original 
films. 

Sound  Inspection. — The  sound-negative  and  the  sound-track  print 
are  turned  over  to  the  Sound  Inspection  Section  and  checked  against 
the  original  recording  log  sheets  and  laboratory  processing  records 
("pink  sheets").  Since  both  sound-negative  and  track-print  will  be 
used  for  printing  (one  for  black-and-white  and  one  for  Kodachrome), 
both  are  carefully  checked  to  make  certain  that  the  film  is  in  prime 
condition  and  that  the  sound  is  up  to  par.  Both  are  then  returned 
to  the  Timing  Section  with  the  report  of  their  condition. 

Timing  of  Picture. — The  Kodachrome  original  is  turned  over 
to  the  timer;  the  procedure  in  timing  Kodachrome  is  quite 
similar  to  that  used  in  timing  black-and-white.  The  timer  de- 
termines the  filter  combination  required,  and  enters  this  and  the 
scene  lights  on  the  timing  sheet.  A  pre-perf orated  timing  strip  is 


168 


W.  H.  OFFENHAUSER,  JR. 


[J.  S.  M.  P.  E. 


TECHNICAL  DATA 

PRECISION  FILM  LABORATORIES 


INVOICE  DATE 


J          L 


GATE  RECEIVED 

CUSTOMER'S  ORDER  NO 

OUROROCRNO 

TERMS.  NET  CASH 

Date  Wanted- 


REEL  NO 

SUBJECT 

ttU& 

FOOTAGE 

OF  STOCK 

REMARKS 

1 

S  m/m     O                Negative    D                Hold           D                B.  &  W.      Q 

•(SUITS  Of  TBTS 

35  m/m     D                Positive       Q                *«»""•        D                Color           D 

Reversal      G                Picture       D                Sound         D                Combined     D 

First  Print 


Subsequent  Print 


Special 


Picture  Printer  #                                                       Emul    #                                                  Weston 

Contact               fj 

Rheo.  Setting                                                  Iris  Setting                                  F"Jr    | 

Optical  1:1     n 

Of.  Ola..  1 

Valt                           Watt  Lamp  Used  At                           Volts 

Reduction         Q 

Head  To  Tail     D                                       Tail  To  Head    Q 

Sound  Printer  •#•                                               Set  At                                              Ampere  With 

Filter  Emul     J  '«       D 

VA  PI             White  Li9ht     D                                    Negative  Emul. 

H.  to  T.  D       T.  to  H.  D 

L-J                UG?         n                                                          Negative  Density 

Print  Density  Detirwl 

YD  D        BG12  n 

Printed  By 

Machine  No.                                                                  Dev.  Time                                    Bath    (  p« 

«"•     n             Gamma 

REMARKS                                                                                                          J»" 

Ml»«     D 

Bath 

ci»l.-  D 
Developed  By 

Picture  Density  )  ^      D                                                 Track   Density   Read     _ 

Quality)^    D 

REPORT 

(r«r     n 

Date 

Inspected  By 

C"      )           f  ro   D        KEMA'"(S 

Date  Released 

U^D      ;U~bK 

Released  By 

fc|                                   REMARKS 

Date 

Incomplete    Q 

FIG.  2.     "Pink  sheet." 

then  made  up  from  the  timing  sheet.  Since  Kodachrome  is  printed 
under  a  weak  green  safelight,  it  is  necessary  that  all  operations  to  be 
performed  in  the  printing  shall  be  done  by  automatic  means  to 
assure  certainty  in  the  result. 

Sound  Inspection  of  Originals. — It  the  meantime,  the  sound-nega- 
tive and  the  sound-track  print  have  been  prepared  and  checked  for 


Aug.,  1943] 


COMMERCIAL  FILM  LABORATORY 


169 


PICTURE 

SOUND 

DEV. 

ORIG.    PRINT 

OEV. 

ORIG.     PRINT 

DEV 

ORIG.    PRINT 

DEV. 

OK  1C 

PRINT 

Fogged 

D 

~Ef  " 

D 

n 

D          G 

Oil  Spots 

'n 

D          D 

G 

G 

G 

Scratches 

n 

n 

D 

n 

D     a 

Water  Spots 

D 

D     n 

D 

G 

a 

Long  D     Int.  Q 

Dirt 

D 

D     n 

n 

G 

a 

Short  D    Steady  G 

Soiled  In  Handling 

D 

G       G 

a 

a 

a 

Cinch  Marks 

{• 

i 

{[ 

{! 

11    {I 

Reticulation 

D 

G       G 

a 

a 

a 

Finger  Marks 

{I 

• 
i 

(1 

(I    il 

Open  Splices 

D 

G       G 

G 

a 

a 

Abrasion  Marks 

[1 

l 

{£ 

{j 

{I    {I 

Broken  Perfs 

n 

G       G 

a 

a 

a 

Emul.  Rubs 

l 

{! 

( 

{1    \l 

Nicked  Perfs. 

n 

G       G 

G 

a 

a 

Off  Sprocket 

D 

n 

D 

n 

a     D 

Hair  Imbedded 

n 

G       G 

a 

G 

a 

Blisters 

D 

a 

n 

n 

a     a 

Hair  In  Neg 

n 

G       G 

a 

a 

G 

Creases 

D 

n 

n 

a 

a     a 

Static 

n 

G       G 

a 

a 

a 

REMARKS 

PICT.                T 

ACK 

n 

n 

RY 

RY 

RY 

PICTURE        i 

SOUND 

PICTURE 

DEV. 

ORIG.     PRINT 

DEV. 

ORIG.    PRINT 

DEV 

ORIG.    PKINT 

DEV. 

ORIG. 

PRINT 

Defective  Printer 

n 

n 

n 

a 

D         D 

Misframed 

n 

G       G 

a 

a 

a 

Light  Out 

D 

n 

n 

a 

a     a 

Mislight 

n 

G       G 

a 

a 

a 

Light  Struck 

n 

n 

n 

a 

D     a 

Mismatched  Emul 

n 

G       G 

a 

a 

a 

Static 

n 

n 

n 

a 

a     a 

Short 

n 

G       G 

D 

a 

a 

Optical  Streaks 

n 

n 

D 

D 

D     a 

Mis  Synchronized 

n 

G       G 

n 

a 

a 

Mistimed 

n 

D 

D 

D 

a     D 

Rewind  Scratches 

n 

G       G 

a 

a 

a 

REMARKS 

RY 

PICTURE 

SOUND 

PICTURE 

SOUND 

DEV. 

ORIG.    PRINT 

DEV. 

ORIG.    PRINT 

OEV 

ORIG.     PKINT 

DEV^ 

ORIG. 

PRINT 

Breaks 

D 

D 

n 

a 

a     n 

Scratches 

n 

15"  IB" 

n 

a 

a 

Creased  Film 

n 

D 

n 

a 

a     n 

Water  Spots 

D 

G       G 

n 

a 

a 

Emul.  Peel 

n 

D 

n 

a 

n     a 

Oil  Spots 

n 

G       G 

a 

a 

a 

Incorrect  Dev. 

D 

n 

D 

n 

a    a 

Streaks 

n 

G       G 

n 

n 

a 

Imperfect  Dry 

n 

n 

n 

a 

a     D 

Stains 

n 

G       G 

a 

a 

a 

Mechanical  Trouble 

n 

D 

n 

n 

a     a 

Stopped  m  Developer 

n 

G       G 

a 

a 

a 

Power  Failure 

n 

D 

n 

i  n 

a     a 

REMARKS 

RY     ' 

CM 

D 

I  Good 

a 

Picture  Density    !+* 

D 

Track  Density  Read 

Quality  {M 

a 

(*-> 

D 

t 

a 

REPORT 

Data 

Inspected  B) 

Damaged  By  Projector 

D 

REMARKS: 

Damaged  Perforations 

D 

Sprocket  Marked 

D 

Soiled  In  Handling 

D 

BY 

iY  CUST.                     IT  PLANT 

REMARKS: 

Incorrectly  Ordered 

n 

n 

Incomplete  Instructions     D 

a 

RY 

FIG.  3.     Reverse  of  Fig.  2. 

printing.  The  sound-track  print,  which  was  made  as  a  fine-grain 
high-quality  track-print,  is  usually  quite  satisfactory  as  a  printing 
master  for  duplicating  the  sound  to  Kodachrome.  As  the  very  best 
in  quality  with  absolute  minimum  of  noise  is  required  in  properly 
produced  instructional  films,  any  defect  (such  as  scratches,  etc.,  how- 


170  W.  H.  OFFENHAUSER,  JR.  \j.  s.  M.  P.  E. 

ever  slight)  will  result  in  the  making  of  a  new  sound-track  print  for 
duplicating  purposes. 

PRINTING 

The  Kodachrome  Test  Duplicate. — The  Kodachrome  original  and 
the  sound-track  positive  are  now  sent  to  the  Kodachrome  printing 
section.  Kodachrome  printing  is  kept  apart  from  black-and-white 
printing  since  only  a  weak  green  safelight  may  be  used  for  Koda- 
chrome. In  this  light,  it  is  almost  impossible  to  read  quickly  due  to 
the  low  level  of  illumination;  for  this  reason,  some  form  of  auto- 
matic pre-set  printing-light-change  arrangement,  such  as  our  pre- 
perforated  light-strip,  is  necessary  for  satisfactory  scene  changes 
despite  the  slow  printing  speed  of  some  twenty  feet  a  minute. 

The  Picture  Printer.— The  improvement  in  lens  resolution  shown 
by  such  projectors  as  the  Eastman  in  comparison  with  the  older 
models  of  other  manufacturers,  as  well  as  the  increasing  use  of  arc 
projectors,  makes  high  resolution  a  "must"  on  Kodachrome  dupli- 
cates.* The  printers  used  for  this  operation  are  step-contact  print- 
ers having  the  movement  claw  within  a  frame  or  two  of  the  aperture 
where  the  duplicate  is  exposed.  Light-changing  is  effected  through 
the  customary  notch  in  the  original ;  in  this  case,  however,  the  notch 
that  effects  the  light-change  automatically  causes  the  pre-perforated 
strip  to  set  the  light-intensity  of  the  particular  scene  being  printed. 

At  this  point,  something  should  be  said  about  picture  printer  de- 
sign and  its  effect  upon  the  resolution  of  the  copy.  Any  conven- 
tional form  of  curved  gate  printer  used  for  continuous  picture  print- 
ing can  provide  good  "contact"  for  only  one  definite  and  specific 
shrinkage  of  the  original  with  respect  to  the  raw-stock  used;  this  is 
determined  by  the  radius  of  curvature  of  the  gate.  It  was  to  avoid 
this  handicap  that  sound-printers  were  forced  to  adopt  the  so-called 
non-slip  construction  in  order  to  be  practical  for  sound-printing 
purposes  by  accommodating  somewhat  wider  shrinkage  ranges. 

Essentially,  the  same  condition  obtains  in  picture-printing,  where 
the  non-conformity  of  the  original  to  the  raw-stock  is  accentuated  by 
the  use  of  acetate-base  materials.  While  there  is  little  or  no  diffi- 
culty with  originals  due  to  different  shrinkages  at  the  center  and  at 
the  edges  when  originals  are  stored  loosely  wound,  a  linear  shrinkage 
of  0.1  per  cent  or  less  in  an  original  when  new  increases  to  a  shrinkage 

*  See  Appendix. 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  171 

of  the  order  of  0.5  per  cent  in  a  relatively  short  time  (less  than  six 
months).  Since  it  is  not  unusual  that  a  film-maker  will  expect  to 
make  prints  from  training  films  that  are  a  year  or  more  old,  curved 
gate  printer  construction  for  Kodachrome  picture  printing  is  elimi- 
nated; the  only  commercial  solution  in  high-quality  Kodachrome 
production  printing  is  slow-speed  step-printing  in  a  straight  gate 
using  a  claw  type  of  film  movement.  It  is  only  in  this  manner  that 
the  contact  printing  ideal — that  of  printing  in  a  still  picture  contact 
frame — can  be  reasonably  well  approximated  with  present-day 
equipment.  All  Kodachrome  printed  at  Precision  Film  Laboratories 
is  printed  on  such  equipment.  It  is  costly,  but  it  preserves  the 
quality  of  the  costly  original. 

The  Sound  Printer. — Over  a  period  of  years,  Precision  Film  Labora- 
tories and  its  affiliated  manufacturing  company,  J.  A.  Maurer,  Inc., 
investigated  the  problem  of  16-mm  sound-track  printing  and  came 
to  the  conclusion  that  ordinary  curved-gate  contact  printing  of  16-mm 
sound-film  was  hopelessly  inadequate  and  that  the  usual  non-slip 
types  were  not  applicable  to  16-mm  acetate-base  films.  If  a  piece 
of  16-mm  film  is  run  between  two  rollers  spaced  even  as  little  as  four 
inches  apart,  the  film  will  appear  to  tilt  first  one  way  and  then  the 
other;  the  effect  seems  aperiodic.  It  does  not  take  much  imagina- 
tion to  visualize  what  happens  when  such  a  film  forms  a  loose  loop 
(as  is  formed  by  the  upper  loop  in  a  non-slip  printer);  such  linear 
non-uniformity  of  one  side  of  the  film  with  respect  to  the  other  can 
not  possibly  produce  good  contact,  especially  with  the  very  low 
value  of  kinetic  energy  provided  by  the  film  in  motion.  There  would 
appear  to  be  no  other  practicable  solution  other  than  to  put  both 
sound-negative  and  sound-positive  under  tension  in  their  respective 
printing  loops  and  to  print  optically  between  them.  It  is  an  open 
secret  among  designers  that  there  are  only  a  very  few  microscope 
objectives  on  the  market  that  can  cover  a  sound-track  with  proper 
field  flatness  and  without  appreciable  illumination  loss  at  the  ends  of 
the  area  to  be  covered;  the  design  problem  included  much  optical 
bench  inspection  of  most  of  the  microscope  objectives  commercially 
marketed.  It  is  interesting  to  note  that  the  lens  selected  as  most 
suitable  for  the  purpose  was  NOT  made  in  Germany. 

Optical  sound- printing  has  several  other  advantages:  it  makes 
possible  quick  interchangeability  of  whatever  color-filters  we  choose 
to  use;  the  depth  of  focus  of  the  optical  system  can  be  made  large 
with  respect  to  the  amount  of  in-and-out-of-focus  film  wobble  ex- 


172  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  P.  E. 

perienced  in  printing;  and  printing  either  emulsion-to-emulsion  or 
base-to-emulsion  can  be  accomplished  at  will.  Last  but  not  least,  it 
provides  an  excellent  means  of  placing  an  image  of  high  resolving 
power  upon  Kodachrome  duplicates;  the  only  means  commercially 
available  that  begins  to  approach  the  resolving  power  of  the  image 
that  would  be  placed  on  Kodachrome  by  a  recording  optical  system 
itself. 

At  this  point,  it  might  reasonably  be  asked  why  picture  is  not 
printed  optically  when  optical  printing  of  sound  has  shown  such  ad- 
vantageous attributes.  The  answer  is  quite  simple;  suitable  optics 
are  not  being  manufactured  and  marketed.  It  has  been  extremely 
difficult  to  find  suitable  optics  for  the  sound-track  area  of  only  one- 
tenth  of  an  inch;  any  attempt  to  cover  three  or  four  times  that  area 
must  be  postponed  until  after  the  war;  then,  we  hope,  suitable  optics 
will  be  marketed. 

After  the  Kodachrome  test  duplicate  has  been  printed,  it  is  packed 
and  shipped  to  the  Eastman  Kodak  Company  at  Rochester  for  color 
developing.  Only  one  print  is  made;  production  prints  are  not 
authorized  until  after  the  test  print  has  beeen  inspected  and  ap- 
proved and  the  small  corrections,  if  any,  requested  by  the  film-maker 
are  incorporated. 

The  Black-and-White  Duplicate  Negative. — While  the  Kodachrome 
test  duplicate  is  in  transit,  the  original  Kodachrome  is  turned  over  to 
the  chief  timer  for  black-and-white  timing  A  timing  sheet  for  the 
black-and-white  duplicate  negative  printing  is  then  prepared; 
from  this  timing  sheet  another  pre-perf orated  timing  strip  is  made  up. 
Within  the  last  two  years  or  so,  we  have  found  it  practicable  to  use 
the  identical  pre-perfprated  timing  strip  for  the  black-and-white 
duplicate  negative  that  was  used  for  Kodachrome  printing.  This 
has  been  possible  since  we  use  the  same  kind  of  printer,  only  one 
make  and  type  of  release-print  fine-grain  film — with  accurate  gamma 
and  density  control;  and  only  one  make  and  type  of  fine-grain  dup- 
licate negative  material* — also  with  accurate  gamma  and  density 
control.  The  film  types  used  were  selected  on  the  basis  of  suita- 
bility for  the  intended  purpose;  strange  to  relate,  all  three  major 
film  manufacturers  are  represented  as  each  seems  to  have  a  special- 
ized technique  in  a  specific  material  which  places  the  particular 
product  "way  out  front." 

*  See  Appendix  for  further  data. 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  173 

The  Black-and-White  Combined  Test-Print. — If  the  duplicate  nega- 
tive is  carefully  made  (and  the  Kodachrome  original  properly  timed 
for  printing),  the  resultant  black-and-white  duplicate  negative  is 
capable  of  producing  highest-quality  release-prints  without  any 
picture  light-change  whatever  in  the  release-printing  operation. 
Here  again,  the  same  kind  of  printers  are  used  as  for  Kodachrome 
printing;  step-contact  printers  with  straight  gates  for  picture  and 
optical  one-to-one  printers  for  sound.  All  films  that  have  been 
shown  to  the  Society  in  the  last  two  years  by  Precision  Film  Labora- 
tories, by  J.  A.  Maurer,  Inc.,  or  by  any  of  the  customers  of  Precision 
Film  Laboratories  have  been  printed  in  the  manner  described. 
Needless  to  say,  considerable  effort  and  planning  were  necessary  to 
put  the  system  into  operation  commercially,  and  a  number  of  prac- 
tical details  had  to  be  worked  out  to  integrate  the  procedure.  As  a 
production  matter,  this  kind  of  procedure  seems  to  be  today's  solu- 
tion of  the  problem  of  high-quality  mass-production  16-mm  black- 
and-white  printing. 

The  Black-and-White  Fine-Grain  Release  Print.- — As  soon  as  the 
black-and-white  test-print  is  inspected  by  the  film-maker,  black-and- 
white  protection  sound-track  prints  are  made;  new  duplicate  nega- 
tives are  made  also  (for  parallel  release  printing  and  for  protection) 
and  the  black-and-white  release-prints  are  "ready  to  roll."  The 
original  sound-negative  is  ordinarily  used  in  all  release  printing; 
it  is  not  unusual  for  as  many  as  a  thousand  or  more  prints  to  be  made 
from  the  sound-negative  original.  With  machinery  properly  de- 
signed, maintained,  and  operated,  sound-negative  deterioration 
should  be  almost  minute.  In  laboratories  that  do  not  specialize  in 
16-mm  film,  here  again  the  "mortality"  rate  runs  quite  high. 

The  Color  Duplicate. — In  the  meantime,  the  color  test  duplicate 
has  been  returned  from  color  development  by  Eastman  Kodak 
Company  and  is  ready  for  inspection.  It  is  screened  by  the  timer 
together  with  the  film-maker ;  the  timer  then  indicates  on  his  timing 
sheet  the  corrections  desired.  A  new  pre-perf orated  timing  strip 
is  made  in  accordance  with  the  corrected  timing  for  the  release  color 
duplicates.  It  is  not  unusual  to  make  as  many  as  two  hundred 
Kodachrome  duplicates  from  the  same  original;  the  uniformity  from 
one  duplicate  to  another  is  just  about  as  good  as  the  color  develop- 
ment uniformity  in  Kodak-processing. 

Multiple  Color  Duplicates. — Experience  indicates  that  if  printing 
machinery  is  well  designed  and  well  maintained,  and  if  the  film  is 


174  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  P.  E. 

carefully  handled  by  competent  and  well  trained  personnel,  few 
printing  "accidents"  will  occur  and  the  two-hundredth  duplicate  of 
a  Kodachrome  original  should  be,  if  anything,  even  better  than  the 
first  or  second,  due  to  the  experience  gained.  Good  machinery 
properly  maintained  and  properly  operated  causes  very  little  wear 
on  an  original  film. 

Multiple  Black-and-White  Prints. — With  regard  to  black-and- 
white  fine-grain  prints,  the  same  may  be  said.  As  the  number  of 
black-and-ivhite  prints  required  of  a  subject  may  run  over  a  thousand, 
some  form  of  parallel  printing  operation  is  necessary  for  volume  out- 
put. The  procedure  outlined  needs  but  one  further  step:  the  pro- 
vision of  a  suitable  number  of  sound-track  negatives  for  printing 
when  a  large  number  of  prints  is  to  be  made  in  a  short  time.  These 
are  best  obtained  by  re-recording;  photographic  methods  are  still 
decidedly  inferior  and  should  not  be  used  if  best  and  most  uniform 
quality  from  print  to  print  is  required.  At  present  commercial  rates, 
sound-tracks  can  be  re-recorded  by  competent  and  properly  equipped 
16-mm  studios  for  as  little  as  $35  to  $50  per  400-ft  reel;  where  a 
number  of  identical  copies  is  to  be  turned  out,  the  price  may  be  even 
lower.  As  it  is  not  unusual  for  a  re-recorded  negative  to  be  used  for 
500  or  more  prints  of  the  same  subject,  the  addition  of  only  some  7 
cents  per  print  to  the  printing  cost  due  to  re-recording  is  one  of  the 
cheapest  kinds  of  good  sound-insurance  that  money  can  buy. 

Kodachrome  and  Black-and-White  Protection  Prints. — When  a 
large  number  of  prints  is  to  be  made  from  an  original  Kodachrome, 
one  of  the  first  matters  for  consideration  is  that  of  "protection  prints." 
In  our  recent  mad  rush  into  16-mm  prints  (from  whatever  originals), 
we  have  paid  the  usual  lip  service  to  protection  prints  but  have  not 
been  especially  concerned  whether  they  fulfilled  their  intended  func- 
tion or  not.  If  it  is  remembered  that  a  protection  print  has  as  its 
function  the  making  of  further  prints  in  the  event  that  the  printing 
master  is  damaged,  not  only  would  considerably  more  care  and 
planning  be  used  in  their  making  but  also  they  would  command  a 
much  higher  price.  To  provide  properly  for  protection  prints,  we 
need  not  only  protection  for  the  picture  but  also  protection  for  the 
sound.  In  the  case  of  the  picture,  the  best  color  protection  print  is  a 
selected  combined  duplicate  from  the  production  run.  No  two 
prints  are  absolutely  identical  in  quality;  if  every  color  duplicate  is 
completely  projection-inspected  (as  is  absolutely  necessary  for 
accurate  quality  control  of  the  product)  it  does  not  take  an  intelli- 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  175 

gent  inspector  very  long  to  select  one  of  the  best  color  duplicates  of 
the  production  run.  As  protection  for  the  black-and-white  prints,  it 
is  advisable  to  make  additional  dupe  negatives  at  the  time  the  extra 
dupe  negatives  are  made  for  the  black-and-white  print  run.  In 
general,  the  number  of  additional  dupe  negatives  made  as  protection 
should  be  a  percentage  of  the  total  number  of  prints  expected  after 
the  initial  print  run  is  completed. 

For  protection  of  the  sound,  the  original  sound-track  print  used 
for  re-recording  the  multiple  black-and-white  re-recorded  negatives 
is  the  best  protection  possible.  If  this  is  in  any  way  scratched  or 
otherwise  damaged,  a  new  print  (sound-track  only)  should  be  made. 
It  is  always  possible  at  a  later  date  to  re-record  from  that  positive 
should  new  printing  negatives  be  needed. 

Specific  Recommendations  for  Protection  Prints. — In  the  case  of  a 
production  where  a  large  print  run  is  planned  for  both  the  Koda- 
chrome  and  for  the  black-and-white,  let  us  say  200  Kodachrome  dup- 
licates and  1000  black-and-white  prints,  the  following  protection 
prints  would  be  desirable : 

(a)  Two  Kodachrome  combined  duplicates  (to  be  used  as  printing  masters  in 
the  event  of  loss  or  damage  to  the  original  picture). 

(6)  Two  black-and-white  sound-track  positive  prints  of  the  original  sound- 
negative.  (One  of  these  would  be  printed  emulsion-to-emulsion  and  the  other 
printed  through  the  base.) 

(c)     Three  new  black-and-white  duplicate  negatives. 

All  of  these,  with  the  possible  exception  of  (a),  should  be  made  at 
the  start  of  the  release  printing  run. 

Reasons  for  These  Recommendations. — (a)  The  combined  dup- 
licates to  be  made  can  be  considered  reserve  master  duplicates;  one 
or  the  other  would  be  used  for  printing  further  release  runs  in  the 
event  of  loss  or  damage  of  the  original.  It  is  to  be  noted,  however, 
that  since  these  films  are  contact-printed,  second-run  duplicates  so 
made  would  have  the  standard  emulsion  position  while  the  original- 
run  duplicates  will  have  the  non-standard  emulsion  position. 

While  there  is  appreciable  photographic  loss  in  release  duplicates 
made  in  this  manner  from  a  master  protection  copy,  it  is  surprising 
how  satisfactory  such  copies  may  be  if  the  original  was  excellent  and 
the  copying  work  accurately  controlled.  It  is  not  unusual  for  such 
secondary-run  duplicates  to  provide  better  screen  quality  than  the 
average  first-run  duplicates  made  in  laboratories  that  do  not  special- 
ize in  16-mm  work. 


176  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  P.  E. 

(b)  One  sound-track  positive  of  the  two  recommended  is  intended 
as  a  protection  sound-positive  to  be  used  in  printing  additional  first- 
run  Kodachrome  sound-duplicates  from  the  original  Kodachrome. 
In  addition,  this  positive  may  be  used  also  for  re-recording  addi- 
tional sound-negatives  for  further  black-and-white  release  runs. 

The  second  sound-track  positive  is  intended  as  a  protection  sound- 
positive  to  be  used  in  printing  second-run  Kodachrome  sound- 
duplicates  from  the  master  protection  Kodachrome  copy. 

(c)  The  black-and-white  duplicate  negatives  recommended  are 
to  be  used  for  later  black-and-white  release  runs;    new  duplicate 
negatives  as  made  for  release-printing  purposes  are  preferably  placed 
in  storage  and  the  older  ones  removed  from  storage  and  used.     In 
this  manner,  the  optimal  state  of  preservation  is  maintained. 

Storage  of  Protection  Prints.— Unfortunately,  one  major  factor 
that  is  responsible  for  the  poor  quality  of  the  16-mm  prints  at  present 
being  purchased  in  very  large  quantity  by  the  Government  for  train- 
ing and  related  purposes,  is  the  absence  of  an  intelligent  protection- 
print  policy.  A  suitable  policy  encompasses  not  only  a  definite  plan 
as  to  how  and  when  and  with  what  quality  protection  prints  are  to  be 
made,  but  also  where  such  prints  are  to  be  stored.  While  much 
specifying  of  protection  prints  is  done,  the  actual  problem  of  where 
and  how  such  prints  are  to  be  stored  has  been  unceremoniously 
dropped  into  the  laps  of  the  release-print  laboratories.  This  has  been 
a  carry-over  from  peace-time  practices  when  laboratories  used  film 
storage  as  a  factor  in  the  competition  for  business. 

The  laboratory  is  NOT  the  proper  place  to  store  these  protection 
prints;  they  should  be  stored  by  the  film-maker  himself,  preferably 
on  his  own  premises,  where  they  are  NOT  out  of  sight  and  out  of 
mind. 

If  the  recommended  protection  films  are  stored  approximately 
one  week  in  the  ordinary  way  and,  at  the  end  of  the  interval,  placed 
in  individual  properly  marked  film  cans  and  mounted  on  cores  some- 
what loosely  wound,  they  will  have  dried  sufficiently  to  be  ready  for 
storage.  The  can  should  be  thoroughly  dried  (carbona  will  both 
clean  and  dry)  and  the  film  put  into  it.  The  can  is  next  sealed  with 
Kodatape  or  other  adhesive  of  equivalent  sealing  ability. 

If  these  cans  are  then  stored  in  an  electrical  refrigerator  whose 
temperature  is  set  for  about  50  degrees,  all  indications  point  to  suit- 
able storage  for  both  the  Kodachrome  (image  deterioration  is  essen- 
tially inhibited)  and  for  the  black-and-white  films.  In  both  cases, 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  177 

shrinkage  is  also  essentially  inhibited;  although  the  film  may  shrink 
somewhat  when  later  taken  out  of  the  can,  the  shrinkage  rate  will  be 
slow  enough  to  permit  the  use  of  the  film  at  least  for  a  period  long 
enough  to  permit  making  the  desired  prints.  The  storage  char- 
acteristics of  16-mm  films  have  improved  considerably  in  the  last 
few  years,  and  still  further  improvement  will  doubtless  come  after 
the  war  is  over. 

Technical  Requirements  of  Protection  and  Other  Good  Prints. — In 
the  JOURNAL  there  are  numerous  papers  on  methods  of  measuring 
and  reducing  residual  hypo.  There  have  also  been  occasional  refer- 
ences to  the  use  of  film  "preservatives."  Unfortunately  proper 
washing  and  drying  of  films  is  the  exception  rather  than  the  rule; 
it  must  be  remembered  that  a  protection  print  provides  no  protec- 
tion whatever  unless  it  is  properly  washed  and  dried. 

"Green"  Film.— On  April  14,  1939,  the  Research  Council  of  the 
Academy  of  Motion  Picture  Arts  &  Sciences  issued  a  Technical 
Bulletin,  "Report  on  Film  Preservative  Tests,"  which  describes 
"green"  film: 

"Treatment  given  to  release-print  film  after  it  has  been  printed,  developed, 
and  dried  is  commonly  called  'film  preserving,'  and  the  processes  by  which  this 
treatment  is  given  are  known  as  'film  preservative'  processes. 

"The  gelatin  of  freshly  developed  film  carries  a  high  percentage  of  moisture  in 
its  pores  and  as  long  as  this  condition  prevails  is  known  as  a  'green'  emulsion. 
A  so-called  'green'  emulsion  is  quite  soft  and  the  slightest  abrasion  will  cause  a 
scratch.  These  scratches  widen  out  as  the  gelatin  dries,  and  cause  the  'rainy' 
effects  seen  on  the  screen  in  the  theater. 

"As  film  with  'green'  or  soft  emulsion  passes  through  a  projector,  it  leaves 
small  deposits  of  emulsion  on  the  tension  shoes  at  either  the  aperture  plate  or 
the  sound-gate,  unless  the  tension  shoes  are  kept  thoroughly  lubricated.  Such 
deposits  build  up  resistance  to  free  passage  of  the  film  over  them,  and  scratch 
the  film  during  projection. 

"When  the  moisture  in  a  'green'  emulsion  is  withdrawn  too  quickly,  the  gelatin 
shrinks  and  the  film  warps  or  buckles.  If  too  great  an  amount  of  moisture  is 
withdrawn  from  the  gelatin,  the  film  becomes  brittle,  loses  its  pliability,  and  is 
easily  torn  while  being  projected." 

The  subject  of  green  film  is  ordinarily  considered  "delicate;"  it  is 
too  often  explained  away  rather  than  investigated.  It  is  not  un- 
reasonable to  believe  that  a  major  source  of  difficulty  with  such  films 
as  those  untreated  films  described  is  just  plain  improper  drying  in 
the  drybox  of  the  developing  machine.  If  one  attempts  to  project 
an  ordinary  mass-produced  low-price  16-mm  "green"  print  made 


178  W.  H.  OFFENHAUSER,  JR.  [jr.  S.  M.  P.  E. 

under  the  average  Government  contract,  it  will  not  even  go  through  a 
projector  without  some  form  of  film  "preservative"  or  lubricant. 

There  are  two  ways  to  look  at  the  problem  of  green  16-mm  prints: 
one  is  to  accept  improper  washing  and  drying  as  a  fact,  and  hope  that 
a  film  "preservative"  will  accomplish  the  miracle;  the  other  is  to 
wash  and  dry  the  film  properly.  This  job  is  not  impossible;  in  our 
laboratory  we  have  been  100-per  cent  projection-inspecting  film  in  a 
matter  of  minutes  after  it  is  removed  from  the  drybox  take-up  of  the 
developing  machine,  and  no  "film  preservative"  whatever  is  used  to 
"ease"  the  film  through  the  projector.  The  reason  is  simple:  the 
film  when  so  washed  and  dried  is  not  green.  This  procedure  is  not 
an  innovation;  the  drybox  is  merely  several  times  as  long  as  the 
developing  tank  and,  in  addition,  excess  hardener  is  used  in  the  hypo. 
In  the  average  case,  the  drybox  of  the  developing  machine  is  only 
about  one-fourth  of  its  proper  length  and  proper  cubic-foot  content 
as  determined  by  the  speed  at  which  it  is  currently  operated.  It 
would  seem  the  better  part  of  wisdom  to  reduce  our  breakneck 
speed  in  order  to  tighten  up  on  our  inspection  and  improve  our 
quality.  It  has  been  too  often  considered  competitively  advanta- 
geous to  run  machines  at  400  feet  per  minute  (in  order  to  cut  prices) 
when  a  fraction  of  the  output  in  the  form  of  really  good  quality  films 
would  far  better  serve  the  ultimate  purpose. 

A  good  rule  to  follow  is  that  if  a  projector  will  not  project  an  un- 
treated new  film  satisfactorily,  there  is  something  wrong  with  the 
film  (most  likely),  something  wrong  with  the  projector  (less  likely), 
or  both.  If  Government  specifications  will  require  that  films  be  pro- 
jection-inspected and  approved  immediately  after  removal  from  the 
developing  machine  and  prior  to  any  "vaporating"  or  "preserving," 
there  will  be  a  remarkable  increase  in  the  life  of  prints  purchased  for 
circulation  as  well  as  a  great  reduction  in  the  waste  of  film,  chemicals, 
and  labor  now  resulting  from  the  scrapping  of  films  that  die  long 
before  their  normal  life  span  should  be  over. 

The  importance  of  proper  washing  and  drying  is  only  now  begin- 
ning to  be  appreciated.  If  we  project  a  carefully  processed  fine- 
grain  film  on  a  12  or  15-ft  screen  with  an  arc  projector  such  as  a  Bell 
&  Howell  equipped  with  sound  and  picture  optics  of  Eastman  Kodak 
quality,  the  film  must  lie  perfectly  flat  in  the  gate  or  in  an  accurately 
predetermined  position  if  the  screen  image  is  to  be  as*  satisfying  as  in 
35-mm  theatrical  projection.  This  is  no  chore  when  films  are  prop- 
erly washed  and  dried;  unfortunately,  proper  washing  and  drying 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  179 

are  not  as  widely  done  as  we  would  all  like.  This  is  another  point, 
incidentally,  where  it  is  possible  for  a  laboratory  to  "cut  corners"  in 
order  to  cut  price. 

High-quality  16-mm  prints  can  now  be  obtained  in  fair  volume 
but,  as  always,  specialization  is  required  properly  to  accomplish  the 
intended  result.  Ordinary  positive  film  does  not  have  sufficient 
resolution  to  provide  the  performance  specified  for  16-mm  films  in 
16-mm  projectors;  fine-grain  films  properly  processed  do  have 
sufficient  resolution,  not  only  for  the  picture  but  also  for  the  sound. 
For  the  sound,  only  optical  one-to-one  printing  can  provide  suitable 
resolution. 

When  properly  processed  fine-grain  films  are  used  in  properly 
designed,  properly  maintained,  and  properly  operated  projectors, 
the  result  is  of  theatrical  quality  and  suitable  for  audiences  (in 
proper  auditoriums  with  proper  screens  and  proper  acoustics)  up  to 
about  500  or  1000.  If  the  result  in  a  particular  case  is  not  satis- 
factory but  the  machinery,  auditorium,  etc.,  are  known  to  be  up  to 
par,  the  film  then  becomes  suspect. 

APPENDIX 

Notes  on  Fine-Grain  Film  and  Its  Processing  in  a  Commercial  16-MM  Laboratory 
General. — While  the  contracts  let  by  the  Government  for  present-day  bulk 
printing  of  war  films  are  quite  long  and  complicated  and  usually  have  a  long  and 
intricate  questionnaire  as  an  integral  part,  a  study  of  the  release-prints  made 
under  such  contracts  seems  to  show  on  the  whole  a  disregard  for  technical  quality. 
In  the  past  emphasis  has  been  placed  upon  quantity  and  low  price  in  an  effort  to 
get  out  the  work;  one  of  the  possible  causes  for  this  one-sidedness  may  well  have 
been  the  paucity  of  reliable  published  data  concerning  the  resolving  power  of 
film  materials  developed  in  commercial  developers. 

It  has  long  been  recognized  that  the  film  to  be  used  for  a  particular  purpose 
should  be  capable  of  clearly  rendering  the  very  fine  lines  of  the  image  to  be  repro- 
duced— whether  the  image  be  of  picture,  of  sound,  or,  for  that  matter,  of  any 
other  form  of  photographic  intelligence.  Generally  speaking,  the  greater  the 
resolving  power  (minuteness  of  detail — measured  in  lines  per  millimeter)  of  the 
films  and  machinery  used  in  the  making  and  showing  of  a  sound-film,  the  better 
the  quality  of  the  performance  seen  and  heard  by  the  audience.  Although  the 
industry  recognized  the  importance  of  resolving  power,  manufacturers  were 
reluctant  to  publish  resolving  power  data  or  to  attempt  to  discuss  the  subject  in 
other  than  qualitative  terms.  "Fine  grain"  was  considered  laudable;  but  there 
was  no  way  for  a  film  user  to  determine  how  fine  "fine  grain"  had  to  be. 

A  convenient  quality  datum  for  16-mm  projection  is  the  quality  obtained  in 
the  conventional  35-mm  entertainment  motion  picture  theater.1  Projection 
equipment,  both  picture  and  sound,  have  been  standardized  and  even  the  theaters 
themselves  have  been  considered  for  standardization.  Sound  has  been  standard- 


180  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  p.  E. 

ized;  the  projection  equipment  characteristics  published  by  the  Academy  of 
Motion  Picture  Arts  &  Sciences  have  been  an  effective  and  reliable  guide  for 
several  years.  With  this  convenient  reference,  it  is  only  necessary  to  extra- 
polate from  the  experience  of  the  larger-size  film  into  that  of  the  smaller. 
If  we  wish  to  match  the  quality  found  in  the  entertainment  motion  picture 
theater  when  we  project  16-mm  prints,  the  latter  prints  must  be  capable  of 
rendering  all  the  detail  of  the  larger  film.  This  is  accomplished,  so  far  as  the 
print  raw-film  is  concerned,  when  the  detail-rendering  ability  of  the  16-mm 
positive  is  equal  to  that  of  its  35-mm  counterpart.  The  resolving  power  of  the 
16-mm  positive  film  must,  therefore,  be  numerically  equal  to  that  of  the  35-mm 
positive  film  multiplied  by  the  ratio  of  the  film  areas.  Since  the  area  to  accom- 
modate the  image  on  the  35-mm  film  is  21/2  times  that  available  to  accommodate 
the  image  on  16-mm  film,  the  resolving  power  of  the  16-mm  film  in  lines  per  milli- 
meter must  be  2l/2  times  that  of  the  35-mm  film  for  equivalent  results. 

The  industry  has  been  most  fortunate  recently  in  obtaining  authoritative  pub- 
lished data  on  the  resolving  power  and  other  characteristics  of  Eastman  film  ma- 
terials.8 The  data  presented  now  make  it  possible  to  judge  quite  reliably  in  a 
quantitative  way  the  most  suitable  Eastman  material  for  a  particular  application. 
The  remainder  of  this  Appendix  will  be  devoted  to  the  practical  application  of 
these  data  and  to  the  suitability  of  the  various  materials  for  their  intended  pur- 
poses. Throughout  this  discussion  it  should  be  borne  in  mind  that  the  difference 
between  35-mm  film  and  16-mm  film  of  a  given  emulsion  type  is  merely  the  width 
to  which  the  material  is  slit;  Eastman  1301  ordinary  positive  35-mm  film,  for 
example,  has  the  same  emulsion  as  Eastman  5301  ordinary  positive  16-mm  film. 

Resolving  Power. — Since  the  resolving  power  of  Eastman  1301  is  55  lines  per 
mm,  it  is  apparent  that  a  16-mm  positive  material  must  have  a  resolving  power  of 
55  X  2x/2  or  1371/2  lines  per  mm  or  more,  for  equal  or  better  performance.  Ac- 
cording to  this  criterion,  Eastman  5302  fine-grain  positive,  while  it  is  a  fine-grain 
material,  is  not  fine  enough  for  the  purpose;  its  resolving  power  is  only  90  lines 
per  mm.  It  is  obvious,  therefore,  that  for  detail -rendering  equal  to  that  of  the 
35-mm  entertainment  motion  picture  theater,  Eastman  5302  fine-grain  will  not 
qualify;  however  Eastman  5365  fine-grain  positive  has  a  resolving  power  of  150 
lines  per  mm,  a  detail-rendering  ability  considerably  beyond  the  minimum  re- 
quired. For  detail-rendering  ability  equal  to  that  of  the  35-mm  entertainment 
motion  picture  theater,  Eastman  5365  is  satisfactory  in  16-mm. 

From  these  figures,  it  should  be  obvious  that  the  use  of  16-mm  ordinary  posi- 
tive materials  such  as  Eastman  5301,  Dupont  600,  Agfa  220,  and  others  of  similar 
resolving  power,  can  not  produce  results  on  a  16-mm  screen  that  are  at  all  com- 
parable with  the  results  found  on  the  usual  35-mm  entertainment  screen.  The 
resolving  powers  of  all  are  of  the  same  low  order.  However,  that  while  Eastman 
5302  does  not  qualify,  it  is  to  be  definitely  preferred  to  material  of  lower  resolv- 
ing power. 

Dupont  has  not  published  data  on  a  comparable  basis.  It  is  known,  however, 
that  Dupont  605  fine-grain  positive  has  resolving  power  of  similar  order  to  that 
of  Eastman  5302.  It  is  to  be  hoped  that  Dupont,  Agfa,  and  the  American 
Gevaert  Company  will  soon  publish  similar  data  on  a  comparable  basis  so  that 
materials  may  be  intelligently  selected  for  their  intended  applications. 

The  Practical  Aspects  of  Application. — Theoretically,  to  preserve  all  the  detail 
of  an  original  film,  it  is  necessary  that  the  resolving  power  of  every  intermediate 


Aug.,  1943]  COMMERCIAL  FILM  LABORATORY  181 

material  and  machine  and  of  the  release-print  material  be  as  high  as  possible  with 
respect  to  the  resolving  power  of  the  original.  This  goal,  while  sought  after,  is 
only  approached;  we  measure  our  achievement  by  the  size  of  the  gap  between 
our  practical  result  and  our  ideal. 

Cost  vs.  Speed. — It  is  true  that  fine-grain  materials  are  inherently  slow  photo- 
graphically; it  was  for  this  reason  that  Dupont,  in  referring  to  Dupont  605  film 
in  their  brochure  "Sixteen  Millimeter  Dupont  Motion  Picture  Film,"  stated, 
"To  date  it  has  been  impossible  to  get  sufficient  light  for  reduction  printers  to 
use  this  slow  film  for  prints  from  35-mm  negatives."  If  the  same  developer  and 
the  same  printing  machine  operating  at  the  same  film  speed  is  used  for  605  as  for 
ordinary  positive,  the  statement  is  true  especially  for  conventional  designs  of 
machinery.  This  film  can  be  used,  however,  if  the  proper  compensating  steps 
are  taken  in  the  proper  amount:  (1)  increasing  the  energy  of  the  developer; 
(2}  increasing  the  intensity  of  the  light-source  or  improving  the  efficiency  of  the 
optics  of  the  exposing  system ;  (3}  reducing  the  linear  speed  of  the  film  through 
the  printer  to  increase  the  exposure  time  by  the  proper  amount.  Just  how  the 
compensating  steps  are  to  be  apportioned  is  a  matter  of  designer's  choice;  re- 
gardless of  the  balance  finally  chosen,  the  cost  of  fine-grain  printing  and  develop- 
ing is  going  to  be  higher  than  the  cost  for  ordinary  positive. 

Gamma. — On  occasion  we  hear  the  remark  "I  tried  fine-grain  film  and  it  didn't 
work."  Further  investigation  usually  shows  some  lack  of  understanding  of  the 
fundamentals  of  film  technique.  One  common  failing  is  the  lack  of  appreciation 
of  the  importance  of  overall  or  print-through  gamma. 

If  we  desire  good  gradation  in  the  picture  image,  it  is  important  that  we  plan 
quantitatively  how  to  obtain  it — we  must  avoid  the  common  fault  of  "piling  up" 
contrast  in  each  successive-processing  step  through  which  the  film  passes.  Fine- 
grain  positive  has  higher  contrast  than  ordinary  positive  and  a  compensating 
reduction  in  gamma  must  be  made  at  some  earlier  stage  if  "washing  out"  is  to  be 
avoided.  It  is  just  as  important  in  1943  to  avoid  "piling  up"  contrast  by  the  in- 
discriminate use  of  high  gammas  as  it  was  in  1929  when  we  first  began  to  appre- 
ciate the  real  significance  of  the  term.  Most  of  the  16-mm  prints  made  under 
the  Government  bulk  printing  contracts  exhibit  an  overall  or  print-through 
gamma  far  too  high  for  even  ordinary  positive  film;  the  use  of  the  same  tech- 
niques in  connection  with  fine-grain  materials  can  not  but  result  in  failure.  Much 
could  be  accomplished  to  correct  this  condition  if  Government  contracts  would 
stress  overall  gammas;  a  very  simple  qualifying  test  for  any  laboratory  desiring  a 
Government  contract  would  be  to  make  a  spliced  test-roll  of  50  feet  containing 
the  original  and  three  sections  of  a  reproduction  from  the  same  reversal  original 
in  sequence — the  first,  the  positive  print  from  the  first  dupe  negative;  the  second, 
the  print  from  the  dupe  negative  of  the  first  positive  print;  and  the  third  the 
print  from  the  dupe  negative  of  the  second  positive  print. 

Contrast  Control. — It  has  been  said  that  one  of  the  most  advantageous  char- 
acteristics of  negative-positive  processing  is  the  control  of  overall  gamma.  This 
excellent  method  is  of  no  value,  however,  if  it  is  not  used — and  most  of  the  16-mm 
prints  show  little  evidence  of  its  use.  If  fine-grain  release-print  materials  are 
inherently  more  contrasty  than  ordinary  positive,  it  is  obvious  that  a  fine-grain 
print  made  from  a  particular  original  will  be  more  contrasty  than  its  ordinary 
positive  counterpart,  whether  the  original  be  35-mm  or  16-mm.  The  original 
negative  must  be  made  "softer,"  or  an  intermediate  master  positive  and  inter- 


182  W.  H.  OFFENHAUSER,  JR. 

mediate  duplicate  negative  of  gamma  product  less  than  unity  must  be  made,  to 
correct  for  the  expected  contrast  increase.  Once  again  the  method  chosen  is  a 
matter  of  designer's  choice,  and  once  again,  regardless  of  the  method  chosen,  it 
will  cost  a  little  more  to  do  the  job  properly  with  fine-grain  film. 

Contrast  control  in  direct  16-mm  black-and-white  is  obtained  by  the  original 
reversal  (Kodachrome) -duplicate  negative-fine-grain  positive  processing  method. 
The  starting  point  is  a  direct  positive;  the  number  of  steps  used  is  one  less  than 
ordinarily  needed  for  optical  reduction  from  35-mm.  In  the  direct  16-mm  case, 
it  should  be  obvious  that  print  contrast  is  controlled  almost  entirely  in  the  making 
of  the  intermediate  duplicate  negative.  The  most  suitable  Eastman  material  is 
Eastman  5203  duplicating  negative;  it  has  a  resolving  power  of  110  lines  per  mm, 
which,  while  a  little  shy  of  the  goal,  is  sufficiently  close  for  practical  purposes. 

Kodachrome. — Kodachrome,  it  should  be  noted,  has  been  unjustly  accused  of 
quality  inherently  inferior  to  that  of  black-and-white  prints.  The  data  pre- 
sented show  the  opposite  to  be  true  in  the  case  of  ordinary  positive;  Kodachrome 
has  a  resolving  power  of  75  lines  per  mm;  Eastman  5301  ordinary  positive  has  a 
resolving  power  of  only  55  lines  per  mm.  If  sound  or  picture  reproduction  in 
Kodachrome  duplicates  is  poorer  than  in  black-and-white  prints  on  ordinary 
positive,  the  fault  should  be  sought  elsewhere  than  in  the  material. 

The  following  table  is  abstracted  from  the  Eastman  publication2  referred  to; 
the  gammas  specified  are  considered  representative  of  good  practice  by  Eastman 
Kodak  Company  but  are  not  necessarily  used  by  Precision  Film  Laboratories. 

Resolving 
Type  Number  Power  Lines  per  Mm  Gamma  Developer 

1301  55  2.0-2.20  D-16 

5302  90  2.40-2.60  D-16 

5365  150  1.20-1.60  *SD-21 

5203  110  0.60-0.70  *SD-21 

REFERENCES 

1  MAURER,  J.  A.:     "Commercial  Motion  Picture  Production  with   16-Mm 
Equipment,"   /.  Soc.  Mot.  Pict.  Eng.,  XXXV  (Nov.,  1940)  p.  437. 

2  MAURER,  J.  A.:    "The  Present  Technical  Status  of  16-Mm  Sound-Film," 
J.  Soc.  Mot.  Pict.  Eng.,  XXXIH  (Sept.,  1939)  p.  315. 

3  OFFENHAUSER,  W.  H.,  JR.,  AND  HARGROVE,  F.  H.:    "Some  Industrial  Appli- 
cations of  Current  16-Mm  Sound  Motion  Picture  Equipment,"    J.  Soc.  Mot. 
Pict.  Eng.,  XXXI  (Feb.,  1940). 

4  SNYDER,  WILBERT  F.:     "Acoustic  Performance  of  16-Mm  Sound  Motion 
Picture  Projectors,"    Bureau  of  Standards  Circular  C439  (July,  1942). 

5  STEPHENS,  ROBERT  E. :    "Optical  and  Mechanical  Characteristics  of  16-Mm 
Motion  Picture  Projectors,"    Bureau  of  Standards  Circular  C437  (June,  1942). 

6  Report  of  the  Committee  on  Non-Theatrical  Equipment:    "Recommended 
Procedure  and  Equipment  Specifications  for  Educational  16-Mm  Projection," 
/.  Soc.  Mot.  Pict.  Eng.,  XXXVH  (July,  1941)  p.  22. 

7  OFFENHAUSER,  W.  H.,  JR.:    "A  Review  of  the  Question  of  16-Mm  Emulsion 
Position,"   /.  Soc.  Mot.  Pict.  Eng.,  XXXIX  (Aug.,  1942),  p.  140. 

8  "Eastman  Motion  Picture  Films  for  Professional  Use,"    Eastman  Kodak 
Company  (Rochester,  N.  Y.),  1942. 


THE  PROJECTION  OF  MOTION  PICTURES 


HERBERT  A.  STARKE** 


Summary. — The  final  phase  of  motion  picture  production  is  in  the  theater,  and 
the  success  of  this  phase  depends  upon  the  technique  of  projection  and  the  condition 
of  the  projection  equipment. 

The  paper  discusses  in  considerable  detail  the  importance  of  proper  maintenance, 
the  types  of  light- sources,  and  other  factors  of  importance  to  good  projection. 


The  final  phase  of  a  motion  picture  production  is  in  the  theater. 
All  the  preparation  and  expenditure  of  money  involved  in  its  creation 
have  now  been  reduced  to  so  much  film  footage.  It  is  now  in  the 
hands  of  the  projectionist,  with  whom  lies  the  responsibility  of  trans- 
ferring the  material  to  the  screen,  through  the  medium  of  projectors 
and  a  source  of  light.  Motion  pictures  are  an  illusion,  and  are  in- 
tended to  convey  realism  to  the  screen. 

Upon  the  arrival  of  the  release  print,  the  normal  procedure  in  first- 
run  theaters  is  a  careful  inspection  and  measurement  of  the  entire 
footage.  For  several  years,  the  exchanges  have  been  doubling  up  the 
reels  of  features  for  shipment.  This  duty  is  performed  for  the  most 
part  by  girls  in  the  exchange.  In  other  words,  the  composite  film  is 
delivered  to  them  on  spools  from  the  laboratory ;  they  in  turn  mount  the 
A  and  B  sections  on  2000-ft  reels.  Our  experience  has  been  that  in 
many  cases,  this  very  important  procedure  is  not  properly  handled. 
Most  of  the  splicing  is  done  with  small  mechanical  splicers,  which  is 
allowed  to  become  worn  and  out  of  alignment,  with  the  result  that 
inaccurate  splices  are  made.  Many  of  the  girls  engaged  in  this  work 
do  not  realize  the  importance  of  properly  blooping  out  splices.  The 
splicing  lacquer  is  allowed  to  become  thick  and  slow-drying;  and  as 

*  Presented  at  the  1942  Spring  Meeting  at  Hollywood,  Calif. 
**  RKO  Service  Corp.,  Hollywood,  Calif. 

183 


184  H.  A.  STARKE  [j.  s.  M.  P.  E. 

re-winding  proceeds,  deposits  from  the  wet  application  are  smeared 
on  the  track  over  several  wraps.  This  necessitates  cleaning  with  a 
lacquer  remover,  and  invariably  the  splices  are  removed.  Under  no 
circumstances  are  the  shipping  reels  used;  they  are,  for  the  most  part, 
badly  bent  and  unfit  for  use.  Most  of  the  best  theaters  are  equipped 
with  cast  aluminum  reels,  upon  which  the  film  material  is  mounted 
for  the  duration  of  the  engagement. 

It  was  the  practice  of  first-run  theaters  in  the  early  days  of  sound  to 
conduct  complete  rehearsals  before  the  opening  of  new  pictures.  The 
chief  projectionist  checked  the  volume  from  the  auditorium,  cues 
were  made,  and  a  general  knowledge  was  acquired  of  the  complete 
show.  Today,  unfortunately,  this  practice  is  not  usually  followed, 
with  the  result  that  the  new  shows  are  opened  without  the  crew's 
having  any  accurate  knowledge  of  the  volume  required.  They  de- 
pend solely  upon  booth  monitoring. 

Projection  room  routine  will  vary  from  theater  to  theater.  Never- 
theless, certain  duties  must  be  performed  daily.  Of  great  importance 
are  the  inspection  and  cleaning  of  the  following  units  : 

(1}  Projector  mechanisms. 

(2}  Upper  and  lower  magazine  valve  assemblies. 

(»?)  Optical  systems. 

(4)  Lamp  houses,  contacts,  and  all  component  parts. 

(5)  Take-ups  and  belts.     Proper  oiling  with  manufacturer's  specified  lubricant. 
Many  projectors  have  been  ruined  by  inferior  oils. 

(6)  Inspection  of  sound  system. 

(7)  Inspection  of  generators  or  rectifiers.     Motor  switches  must  be  replaced  at 
regular  intervals.     A  failure  here  may  cause  interruption  of  the  performance. 

It  is  important  that  the  light  from  each  projector  be  checked  on  the 
screen  for  intensity  and  color,  and  at  the  same  time,  image  alignment 
should  be  checked.  Every  effort  should  be  made  to  ascertain  that  the 
shutters  are  perfectly  timed ;  slight  bleeding  that  may  not  be  observed 
from  the  projection  room  will  cause  loss  of  definition. 

There  appears  to  be  considerable  lack  of  showmanship  today,  and 
the  absence  of  lighting  effects  is  noticeable.  The  general  procedure  is 
to  work  out  a  schedule,  the  starting  time  is  determined,  and  the  show 
is  on.  The  practice  of  giving  away  cash  and  other  prizes,  in  many  of 
our  de  luxe  theaters  has  not  enhanced  the  production  but  rather  has 
cheapened  it. 


Aug.,  1943]  PROJECTION  OF  MOTION  PICTURES  185 

The  success  of  the  presentation  depends  largely  upon  technical  con- 
ditions often  beyond  the  control  of  the  projectionist.  The  equip- 
ment in  many  of  our  theaters  today  is  inadequate,  particularly  with 
respect  to  the  available  light,  Theater  managers  seem  to  be  reluctant 
to  seek  proper  advice  when  purchasing  lamp  equipment,  and  false 
economy  often  results  in  inadequate  projection.  * 

Light  sources  may  be  divided  into  three  categories:  (1)  the  largest 
theaters  require  condenser-type  high-intensity  arcs ;  (2)  the  interme- 
diate theaters  the  Suprex  type;  (5)  and  the  small  theaters  the  1-kw 
a-c  or  d-c  types.  Due  to  its  yellow  color  and  low  intrinsic  brilliancy, 
the  low-intensity  arc  is  being  rapidly  replaced  by  an  intermediate 
type  of  non-rotating  high-intensity  arc  having  a  color  value  approxi- 
mating the  white  light  of  the  rotating  and  non-rotating  high-intensity 
arcs.  The  reflected  screen  light  depends  upon  the  character  of  the 
source,  the  optical  system,  and  the  reflectivity  of  the  screen ;  and  last 
but  not  least,  upon  the  efficiency  of  operation.  To  the  projectionist 
falls  the  task  of  coordinating  these  elements  into  a  single,  smoothly 
operating  whole. 

Dense  prints  are  quite  common  today,  and  it  is  also  becoming  the 
practice  to  increase  the  auditorium  illumination.  Smoking  is  per- 
mitted in  many  theaters,  tending  to  decrease  reflectivity  of  the  screen. 
The* projectionist  in  the  large  theaters  using  the  Suprex  equipment  in- 
stead of  the  high-intensity  condenser  arcs  will  often  increase  the  arc 
wattage  beyond  the  rated  capacity  of  the  carbon  trim  in  an  attempt 
to  increase  the  brightness  of  the  picture.  He  then  encounters  a  dis- 
proportionate increase  in  carbon-burning  rate,  often  beyond  the  feed 
rate  of  the  arc  control  mechanism.  Operation  then  becomes  critical 
and  efforts  at  manual  control  prevent  the  arc  from  establishing  itself 
on  a  stable  basis. 

There  has  been  a  tendency,  particularly  on  the  West  Coast,  to  in- 
crease the  picture  size  without  adding  to  the  illuminations,  whereupon 
a  reduction  in  brightness  and  contrast  results.  Graininess  is  also 
noticeable,  and  all  these  factors  lessen  the  value  of  the  front  rows  of 
seats. 

Operating  difficulties  may  be  encountered  with  the  rotating  high- 
intensity  lamp,  due  to  pitted  or  burned  contact  brushes,  loose  and 
dirty  lead  connections,  excessive  voltage  at  the  arc.  The  carbon 
manufacturers'  specifications  should  be  rigidly  followed.  The  lamp 
house  should  be  ventilated,  if  possibe,  with  a  separate  exhaust  fan, 
and  dampers  put  into  the  stack  in  such  a  manner  as  to  control  the 


186  H.  A.  STARKE  [j.  s.  M.  P.  E. 

travel  of  air  without  impeding  the  passage  of  waste  materials  of  arc 
combustion. 

The  Suprex  and  the  1-kw  types  of  non -rotating  high-intensity 
lamps  are  operated  at  small  arc  voltage  and  current.  Hence,  they 
are  sensitive  to  drafts.  Modern  lamp  houses  are  designed  to  have 
sufficient  ventilation  under  ordinary  conditions,  but  close  control  of 
the  amount  of  air  passing  through  the  lamp  houses  into  the  stack  is 
essential  for  trouble-free  operation.  Abnormal  draft  is  caused  by 
excessive  ventilation  of  the  projection  room,  back-draft  from  certain 
types  of  rear  shutters  having  cooling  fins,  and  down  drafts  from  chim- 
neys lacking  forced-draft  ventilation.  Excessive  draft,  unless  very 
strong,  does  not  usually  cause  flickering,  but  it  does  cause  a  move- 
ment of  the  arc  flame,  which  becomes  noticeable  on  the  screen. 

The  non-rotating  high-intensity  arc,  when  properly  burned,  is 
almost  rectangular  in  form,  with  the  point  of  the  tail  flame  directly 
above  and  not  far  behind  the  positive  crater.  If  the  tail  flame  wavers 
and  is  driven  toward  the  front  of  the  lamp  house  in  an  intermittent 
manner,  excessive  draft  is  usually  indicated. 

If  it  is  not  possible  to  control  the  draft  with  the  stack  damper,  it  may 
be  necessary  to  restrict  the  ventilation  entering  the  lamp  house;  or, 
if  the  trouble  is  caused  by  fins  on  the  rear  shutters,  the  fins  may  be 
removed.  However,  this  procedure  is  not  recommended,  as  the  fins 
were  installed  to  dissipate  heat  from  the  film  and  the  film-trap  assem- 
bly. It  is  suggested  that  the  arc  be  protected  by  means  of  a  heat- 
proof glass  shield  placed  directly  behind  the  rear  shutters.  It  should 
be  remembered,  however,  that  adequate  ventilation  is  necessary  to 
protect  the  lamp  house,  and  drafts  should  be  restricted  only  to  the 
point  at  which  the  arc  will  burn  satisfactorily. 

In  order  to  maintain  a  rectangular  arc  shape,  as  described,  it  is 
necessary  that  the  carbons  be  properly  positioned,  by  raising  and 
lowering  the  negative  carbon  until  the  gases  are  seen  to  escape  from 
the  top  of  the  positive  crater.  For  higher  currents,  the  negative  car- 
bon tip  should  be  slightly  below  the  centerline  of  the  positive,  and  in 
order  to  let  the  gases  escape  from  the  top  of  the  crater,  it  may  be 
necessary  to  allow  the  top  of  the  positive  crater  to  burn  back  as  much 
as  0.32  inch. 

Anything  that  disturbs  the  normal  position  or  function  of  the  arc, 
such  as  some  types  of  carbon  savers,  or  by  burning  the  carbons  too 
short,  may  result  in  screen  discoloration,  light  reduction,  or  change 
in  light  distribution. 


Aug.,  1943]  PROJECTION  OF  MOTION  PICTURES  187 

The  optical  system  of  the  non-rotating  high-intensity  lamp  is  de- 
signed by  the  manufacturer  to  deliver  the  maximum  amount  of  light, 
and  the  arc  should  be  operated  in  a  given  position  with  respect  to  the 
mirror.  Moving  the  positive  crater  toward  the  mirror  0.10  inch  from 
its  proper  distance  will  result  in  a  decrease  in  screen  illumination  of 
approximately  40  per  cent  when  using  a  7-mm  positive  carbon. 

In  order  to  avoid  noticeable  screen  color  difference,  the  arc  should 
be  struck  three  or  four  minutes  before  the  change-over  period  and 
the  position  of  the  image  of  the  positive  crater  should  be  adjusted 
before,  not  after,  the  change-over.  In  many  theaters  where  false 
economy  prevails,  projectionists  are  instructed  never  to  strike  the 
arc  on  the  incoming  projector  until  the  last  minute.  With  this  pro- 
cedure, screen  results  are  bound  to  suffer. 

When  illumination  trouble  occurs  it  is  necessary  to  locate  it  with  a 
minimum  of  delay.  Unfortunately,  it  is  often  difficult  to  determine 
immediately  whether  or  not  the  carbons  are  at  fault,  and  some  pro- 
jectionists keep  a  few  trims  in  a  dry  place  to  be  used  as  a  check.  Later 
if  trouble  occurs,  carbons  being  currently  used  are  checked  against 
these  reserves.  If  the  trouble  persists,  one  may  look  elsewhere  for  it, 
such  as  in  the  current  supply  or  in  the  condition  of  the  draft.  Rarely 
are  the  carbons  found  to  be  at  fault. 

With  the  releasing  of  productions  on  fine-grain  stock,  hopes  were 
entertained  that  some  of  the  lighting  problems  would  be  lessened. 
Experience  in  this  respect  has  been,  to  say  the  least,  very  disappoint- 
ing. The  greater  brilliance  and  contrast  are  readily  apparent,  but 
the  stock  used  so  far  has  a  tendency  to  buckle.  The  phenomenon  is 
very  curious:  it  comes  and  it  goes.  A  print  may  be  used  for  a  few 
days  without  trouble;  then,  for  no  apparent  reason,  the  picture  on 
the  screen  begins  to  weave  in  and  out  of  focus.  In  other  words,  the 
photographic  image  will  be  out  of  focus. 

The  modern  projector  is  designed  to  be  adaptable  to  all  types  of 
theaters.  There  are,  however,  many  mechanisms  now  in  use,  par- 
ticularly in  circuit  houses,  that  should  have  been  discarded  years  ago. 
Worn  film-tracks  and  hooked  sprockets  are  found  in  many  of  them, 
which  are  the  causes  of  film  damage  in  alarming  proportions.  Many 
projectionists  have  adopted  the  practice  of  speeding  up  their  electric 
rewinds  beyond  the  limits. set  by  the  manufacturers.  This  causes 
many  fine  scratches  on  the  surface  of  the  film,  commonly  called 
"rain,"  and  should  not  be  tolerated. 

It  is  difficult  to  understand  why  so  many  owners  and  managers  will 


188  H.  A.  STARKE  [j.  s.  M.  P.  E. 

not  hesitate  to  make  large  expenditures  on  new  marquees,  carpets, 
chairs,  and  on  the  general  beautifying  of  the  auditorium,  all  of  which 
can  not  be  fully  appreciated  in  the  dark,  but  neglect  to  maintain 
properly  the  most  vital  part  of  their  theater — the  projection  equip- 
ment. The  screen  is  allowed  to  become  dirty  and  discolored.  There 
are  many  methods  of  so-called  resurfacing;  few  have  proved  satis- 
factory. The  best  procedure  is  to  try  to  keep  the  surface  and  perfora- 
tions free  from  dust  and  dirt.  When  discoloration  does  take  place, 
the  screen  should  be  replaced.  The  difference  in  cost  between  an  or- 
dinary resurfacing  job  and  a  new  screen  is  not  comparatively  great. 

Many  of  the  older  theaters  were  constructed  during  the  days  of 
vaudeville  and  stage  presentations.  The  picture  was  of  secondary 
importance;  consequently  little  if  any  attention  was  given  to  the 
planning  of  the  projection  room,  which,  with  very  few  exceptions, 
were  small  and  poorly  ventilated.  They  were,  in  most  cases,  con- 
structed high  above  the  balcony  to  avoid  the  loss  of  seating  space. 
The  cost  of  redesigning  them  to  present-day  standards  would  be  pro- 
hibitive. 

Picture  distortion  and  keystoneing  are  present.  Squaring  the  pic- 
ture image  by  aperture-plate  correction  improves  the  general  appear- 
ance, but  the  situation  is  a  serious  handicap  to  good  projection.  It  is 
unfortunate  that  such  conditions  prevail  in  many  of  our  first-run 
houses. 

Notwithstanding  these  and  many  other  factors,  projection  has  for 
the  most  part  improved  steadily. 

In  1936  the  Research  Council  of  the  Academy  of  Motion  Picture 
Arts  &  Sciences  recommended  the  standard  leader  and  the  placing  of 
dots  in  the  upper  right-hand  corner  of  the  composition  for  change-over 
cues.  This  practice  was  adopted  by  all  the  large  producing  com- 
panies, and  provides  a  successful  means  of  properly  changing  from  one 
reel  to  another.  Yet  there  are  still  some  projectionists  who  deliber- 
ately deface  the  ends  of  reels  with  cues  of  their  own  design,  such  as 
punch  marks  or  crosses  scratched  into  the  emulsion,  all  tending  to 
impair  the  print  and  detract  the  audience's  attention  from  the  sub- 
ject being  reproduced  upon  the  screen.  True,  the  laboratories  do  not 
provide  standard  cues  on  many  short  subjects,  such  as  newsreels  and 
trailers,  and  it  is  necessary  that  some  sort  of  cue  be  provided.  A  small 
inexpensive  cue-marker  consisting  of  a  template  and  a  hardened 
steel  scriber  is  recommended,  for  .scribing  a  small  circle  at  the  upper 


Aug.,  1943]  PROJECTION  OF  MOTION  PICTURES  189 

right-hand  corner  of  the  film  image,  at  exactly  the  spot  where  the 
standard  dots  would  appear. 

Conservation  is  all-important  today,  and  replacement  parts  will 
not  be  obtainable.  It  is  therefore  urgent  that  equipment  should  be 
properly  checked  and  adjusted.  There  is  no  reason  why  an  intermit- 
tent sprocket  should  not  last  at  least  three  years,  provided  it  is  of  the 
manufacturer's  specifications  and  the  tension  pads  and  shoes  are 
properly  adjusted.  Excessive  tension  not  only  shortens  the  life  of  the 
sprockets,  but  also  causes  undue  wear  throughout  the  entire  projector 
mechanism.  One  method  of  increasing  the  life  of  tension  pads  and 
shoes  is  to  have  them  ground  perfectly  true  and  then  chromium- 
plated.  This  also  eliminates  the  tendency  of  new  (or  "green")  film  to 
stick  while  being  projected. 

Space  does  not  permit  a  complete  discussion  of  the  many  important 
units  that  tend  to  make  up  the  modern  projection  room.  Projection 
may  be  termed  the  bottle-neck  of  the  industry,  and  there  is  much  that 
can  be  done  in  the  projection  room  to  assist  in  placing  upon  the  screen 
high-quality  pictures  reflecting  the  great  amount  of  labor,  art,  and 
expense  that  went  into  the  making  of  the  production  in  the  studio. 


APPLICATION  AND  DISTRIBUTION  OF  16-MM 
EDUCATIONAL  MOTION  PICTURES* 


F.  W.  BRIGHT*5 


Summary. — The  proper  distribution  and  application  of  16-mm  motion  pictures 
require  painstaking  planning  and  continued  follow-through.  .  With  this  in  mind,  the 
methods  of  distribution  are  considered  with  respect  to  the  three  major  fields  of  business 
employing  16-mm  pictures,  viz.,  (1)  public  education;  (2)  sales  training;  (3)  per- 
sonalizing messages  from  home  offices  to  field  personnel. 


The  proper  application  and  distribution  of  16-mm  motion  pictures 
is  not  a  hit-or-miss  proposition.  Rather  it  is  an  exact  science  de- 
pending almost  entirely  upon  painstaking  planning  and  continued 
follow-through. 

Too  often  producers  and  users  of  16-mm  pictures  neglect  to  give 
this  phase  of  the  program  the  necessary  attention.  Too  much 
emphasis  is  placed  upon  achieving  mechanical  perfection  in  the 
picture,  and  too  little  upon  the  ultimate  effect  upon  the  audiences, 
with  the  result  that  the  picture  fails  in  the  job  for  which  it  was  in- 
tended. 

Since  1934,  when  we  distributed  our  first  16-mm  public  release, 
the  results  of  this  medium  of  visual  and  oral  education  have  been 
excellent,  because  the  application  and  distribution  plans  have  been 
carefully  considered  well  in  advance  of  the  release  dates. 

At  present  we  are  enthusiastically  producing  and  using  16-mm 
films  in  three  major  fields — (1)  public  education,  (2)  sales  training, 
and  (3)  personalizing  messages  from  Home  Office  officials  to  our 
field  personnel. 

Public  Education. — Before  releasing  any  picture  for  the  public, 


*  Presented  at  the  1942  Fall  Meeting  at  New  York,  N.  Y. ;  received  October 
25,  1942. 

**  Supervisor,  Motion  Picture  Bureau,  The  Aetna  Casualty  and  Surety  Co., 
Hartford,  Conn. 
190 


EDUCATIONAL  MOTION  PICTURES  191 

the  distribution  is  carefully  planned,  step  by  step.  This  procedure 
is  demonstrated  by  one  of  our  educational  health  releases.  The 
first  step  in  planned  distribution  is  to  arrange  formal  previews  by 
recognized  authorities  on  the  subject.  Invited  to  these  previews 
are  representatives  of  the  local  or  state  medical  societies,  key  members 
of  hospital  staffs,  dietitians,  representatives  of  stand  and  local 
health  departments,  and  others  who  have  a  real  interest  in  the  sub- 
ject. After  seeing  the  picture,  they  are  asked  to  offer  suggestions 
and  criticisms.  If  the  criticisms  are  of  sufficient  importance  and 
are  practical,  we  make  the  necessary  changes.  This  procedure 
guarantees  authenticity  and  saves  us  the  embarrassment  from 
justifiable  criticism  after  release  to  the  public. 

The  second  step  is  a  formal  premiere  of  the  picture.  Even  though 
it  may  be  necessary  to  hold  up  the  release  date  for  some  time,  the 
picture  is  given  its  premiere  at  a  national  convention  or  meeting 
of  a  group  who  are  vitally  interested  in  promoting  the  subject.  At 
this  meeting,  however,  it  is  important  that  the  picture  be  an  integral 
part  of  the  program  rather  than  on  a  commercial  exhibitor's  basis. 
This  showing  gives  us  a  good  cross-section  of  public  reaction,  creates 
good  will  for  our  companies,  and  provides  an  excellent  vehicle  for 
publicizing  the  picture  through  newspapers,  radio,  and  word  of 
mouth. 

The  third  step  is  the  public  announcement.  Carefully  worded 
copy  is  sent  to  selected  trade  publications  whose  readers  will  have 
a  natural  interest  in  the  picture.  Personal  letters,  including  copies 
of  the  news  release  are  mailed  to  a  large  list  of  individuals  and 
organizations  throughout  the  country.  Simultaneously  announce- 
ment is  made  to  all  our  field  offices  and  an  article  is  inserted  in  our 
house  organ  which  reaches  some  25,000  agents. 

After  we  have  carefully  followed  these  various  steps,  the  picture 
is  released  publicly  and  a  large  number  of  requests  automatically 
follow. 

To  increase  distribution  further,  we  have  equipped  twenty-five, 
strategically  located  field  offices  with  sound  projectors  and  screens. 
These  offices  then  follow  through  on  their  local  distribution  plans, 
offering  to  project  the  picture  to  certain  key  groups  and  offering  prints 
without  charge,  to  others.  Furthermore,  each  of  these  offices 
serves  as  a  booking  office  and  depository  for  the  film.  Their  pro- 
jection equipment,  as  well  as  prints,  are  inspected  periodically  and 
monthy  reports  of  their  showings  are  obtained.  They  maintain 


192  F.  W.  BRIGHT  [j.  s.  M.  P.  E. 

their  own  schedules  and  any  agents  in  their  territories  who  are 
qualified  to  operate  the  projection  equipment  may  borrow  it  without 
charge. 

Proof  of  the  effectiveness  of  this  distribution  plan  for  public  re- 
leases is  evidenced  by  the  fact  that  one  of  our  pictures  alone  was 
shown  to  more  than  20,000,000  persons  before  it  became  too  dated 
and  was  withdrawn  from  circulation. 

Sales  Training. — In  showing  sales  training  pictures,  distribution 
volume  is,  of  course,  secondary  to  proper  application.  Like  many 
businesses,  we  have  a  certain  number  of  commissioned  salesmen  who 
either  have  had  no  previous  selling  experience,  or  at  least  are  new- 
comers to  our  business.  Following  the  war,  all  business  employing 
large  numbers  of  salesmen  will  be  faced  with  the  problem  of  at- 
tracting desirable  representatives.  Since  the  competition  will  be 
so  keen,  we  feel  that  our  experience  now  with  motion  pictures  will  be 
invaluable  in  this  recruiting  work. 

Just  as  distribution  is  carefully  planned  before  production  of 
public  release  subjects,  the  application  of  sales-training  pictures  is 
also  planned  in  detail  before  production  commences.  Sales-training 
subjects  are  broken  down  into  two  general  classifications:  (a)  basic 
selling  suggestions,  and  (b)  technical  sales  training.  The  basic 
selling  suggestions  type  is  used  for  primary  training  of  new  men,  and 
as  refreshers  for  experienced  salesmen.  In  these  pictures,  we  in- 
clude proper  technique  for  pre-approach,  approaching  the  prospect, 
organizing  the  details  of  a  selling  campaign,  asking  leading  questions, 
and  other  details  which  even  seasoned  salesmen  may  neglect.  Since 
the  subject  matter  is  usually  trite,  there  is  a  tendency  to  treat  it 
lightly,  so  the  points  are  dramatized  to  an  exaggerated  degree.  By 
carefully  planning  the  material  in  these  films,  they  are  acceptable 
not  only  to  our  own  personnel,  but  through  our  trade  organizations, 
we  can  attract  new  salesmen  to  our  companies.  Technical  training 
pictures  for  salaried  representatives  and  more  advanced  agents  pro- 
vide an  excellent  medium  for  introducing  new  contracts,  developing 
particular  sales  possibilities  and  dramatizing  the  benefits  as  well  as 
the  limitations  of  our  contracts. 

In  the  production  of  all  sales-training  pictures,  we  work  closely 
with  our  sales  department  in  deciding  the  subject  matter,  preparing 
the  script,  casting  the  actors,  and  other  production  details.  While 
sound  slide  films  and  post-recorded  motion  pictures  have  a  definite 
place  in  visual  education,  we  have  learned  that  lip  synchronization 


Aug.,  1943]  EDUCATIONAL  MOTION  PICTURES  193 

gives  the  best  results,  particularly  in  dramatizing  sales  interviews 
where  voice  inflection  and  timing  are  important.  A  close  check  is 
kept  on  the  audience's  reaction  to  these  sales  pictures  and  suggestions 
from  our  field  representative  is  welcomed.  Fortunately,  we  have 
little  difficulty  in  learning  how  the  pictures  are  received  by  our  agents. 
Following  nearly  every  showing,  we  receive  letters,  all  of  them  ap- 
parently sincere  and  spontaneous,  since  criticism  is  made  as  freely 
as  praise. 

Personalizing  Messages  from  the  Home  Office. — Because  of  restricted 
transportation  facilities,  we  have  had  to  curtail,  to  a  great  extent, 
visits  to  our  field  offices.  Consequently,  this  has  increased  the  need 
for  localized  educational  meetings  of  branch  office  personnel  and 
agents.  By  utilizing  16-mm  lip  synchronization  we  have  been  able 
to  bring  educational  and  inspirational  talks  by  our  key  men  to  these 
local  meetings.  This  year,  for  example,  at  our  annual  sales  meet- 
ings, which  are  held  in  some  twenty-five  field  offices,  we  reduced  our 
traveling  personnel  to  a  minimum;  yet  at  the  same  time,  via  motion 
pictures,  took  approximately  forty  of  our  officers  and  specialists  to 
these  meetings. 

The  sound  projectors  that  we  have  placed  in  certain  of  our  branch 
offices  are  always  readily  available  for  both  sales  training  and  per- 
sonalized messages,  and  since  they  are  portable,  they  can  be  used  in 
not  only  the  offices,  but  in  hotels  and  other  meeting  places. 

When  we  first  released  16-mm  motion  pictures  publicly,  we  at- 
tempted to  supply  all  requests  within  a  short  time,  but  soon  found 
that  it  was  impossible.  For  example,  we  used  nearly  600  prints  of 
one  highway  safety  film,  and  even  this  large  number  was  insufficient. 
Moreover,  some  of  our  pictures  are  released  exclusively  in  color  and 
since  they  run  eight  hundred  to  twelve  hundred  feet,  the  cost  of 
hundreds  of  prints  is  prohibitive.  Rather  than  diminishing,  the 
demand  for  pictures  increased,  and  we  had  to  limit  the  number  of 
prints  of  each  picture  available.  All  our  subjects  are  produced  in 
kodachrome  from  which  we  make  black-and-white  dupes,  and  al- 
though some  of  them  are  released  in  color,  all  the  sales  training  and 
most  of  the  public  releases  do  a  satisfactory  job  in  black  and  white. 
We  now  limit  the  number  of  prints  to  forty  black  and  white  and  ten 
kodachrome.  Black-and-white  prints  are  then  deposited  in  our 
branch  office  depositories  and  the  remainder  booked  direct.  In 
cases  where  color-prints  are  distributed  exclusively,  the  entire  booking 
and  distribution  are  handled  from  our  home  office. 


194  F.  W.  BRIGHT 

Naturally  there  must  be  exceptions  to  this  plan.  Shortly  after 
Pearl  Harbor,  we  produced  a  civilian  defense  picture  in  cooperation 
with  the  Connecticut  Defense  Council  and  intended  it  to  be  used 
only  in  Connecticut.  However,  we  soon  received  requests  from 
neighboring  states,  and  the  demand  increased  until  today  we  are 
using  sixty  prints  in  all  parts  of  the  country.  To  help  keep  up,  with 
the  demand  for  this  and  other  pictures,  after  we  have  exhausted  our 
budget  on  the  picture,  we  make  prints  available  at  cost  to  interested 
non-commercial  organizations.  Local  and  state  defense  councils, 
service  clubs,  colleges,  safety  councils,  and  similar  groups  have 
purchased  prints  and  in  each  case,  we  prepare  a  short  credit  title 
showing  their  sponsorship  of  the  picture. 

While  we  are  planning  to  maintain  our  motion  picture  program 
as  far  as  possible,  the  war  has  already  made  some  changes  and  will 
undoubtedly  affect  our  distribution  and  application  materially. 
However,  we  hope  to  adhere  to  two  main  types  of  pictures — -public 
education  along  the  lines  of  conservation,  health  and  safety;  and 
education  of  our  agents  and  others  in  our  sales  force.  We  are  also 
experimenting  with  sales  presentation  pictures  which  our  agents  can 
take  directly  into  the  prospect's  home  or  office  and  which  will  give 
him  an  opportunity  to  get  and  hold  the  prospect's  attention  with  the 
power  of  16-mm  motion  pictures.  We  have  already  made  some 
progress  along  this  line,  and  after  the  war  is  over,  we  shall  be  ready 
to  use  this  new  application  of  the  motion  picture  medium. 


FIFTY-FOURTH  SEMI-ANNUAL  TECHNICAL  CONFERENCE 


OF  THE 


SOCIETY  OF  MOTION  PICTURE  ENGINEERS 


HOLLYWOOD-ROOSEVELT  HOTEL,  HOLLYWOOD,  CALIF. 
OCTOBER  18-22,  INCLUSIVE 


Officers  and  Committees  in  Charge 

HERBERT  GRIFFIN,  President 

EMERY  HUSE,  Past- President  and  Chairman,  Local  Arrangements 

LOREN  L.  RYDER,  Executive  V 'ice-President 

W.  C.  KUNZMANN,  Convention  Vice- President 

A.  C.  DOWNES,  Editorial  Vice-President 

E.  A.  WILLIFORD,  Secretary 

C.  W.  HANDLEY,  Chairman,  Pacific  Coast  Section 

JULIUS  HABER,  Chairman,  Publicity  Committee 

Papers  Committee 


C.  R.  DAILY,  Chairman 
C.  R.  KEITH,  Vice-Chairman  East  Coast 


F.  W.  BOWDITCH 

G.  A.  CHAMBERS 
F.  L.  EICH 

R.  E.  FARNHAM 
J.  L.  FORREST 


J.  FRANK,  JR. 
J.  G.  FRAYNE 
P.  A.  McGuiRE 
E.  W.  KELLOGG 
G.  E.  MATTHEWS 


H.  W.  MOYSE 

W.  H.  OFFENHAUSER 

V.  C.  SHAUER 

S.  P.  SOLOW 

W.  V.  WOLFE 


Reception  and  Local  Arrangements 


H.  J.  CHANON 
J.  G.  FRAYNE 

A.  M.  GUNDELFINGER 

C.  W.  HANDLEY 
E.  H.  HANSEN 
J.  K.  HILLARD 
E.  M.  HONAN 


C.  W.  HANDLEY 
E.  HUSE 


EMERY  HUSE, -Chair man 
M.  S.  LESHING 
W.  C.  MILLER 

R.  H.  McCULLOUGH 

P.  MOLE 
F.  K.  MORGAN 
H.  W.  MOYSE 
W.  A.  MUELLER 

Registration  and  Information 

W.  C.  KUNZMANN,  Chairman 


G.  F.  RACKETT 

H.  W.  REMERSHIED 

L.  L.  RYDER 

C.  R.  SAWYER 

S.  P.  SOLOW 

J.  R.  WILKINSON 

W.  V.  WOLFE 


R.  G.  LlNDERMAN 

H.  SMITH,  JR. 


195 


196        FIFTY- FOURTH  SEMI- ANNUAL  CONFERENCE         tf.  s.  M.  p.  E. 

Publicity  Committee 

JULIUS  HABER,  Chairman 

J.  W.  BOYLE  G.  R.  GIROUX 

C.  R.  DAILY  C.  R.  KEITH 

G.  GIBSON  E.  C.  RICHARDSON 

Luncheon  and  Dinner-Dance  Committee 

LOREN  L.  RYDER,  Chairman 

A.  M.  GUNDELFINGER  P.  MOLE  R.  R.  SCOVILLE 

H.  T.  KALMUS  H.  W.  MOYSE  S.  P.  SOLOW 

E.  M.  HONAN  W.  A.  MUELLER  J.  R.  WILKINSON 

E.  HUSE  H.  W.  REMERSHIED  W.  V.  WOLFE 

Hotel  and  Transportation 

A.  M.  GUNDELFINGER,  Chairman 

A.  C.  BLANEY  A.  F.  EDOUART  O.  F.  NEU 

L.  W.  CHASE  H.  GOLDFORB  G.  E.  SAWYER 

H.  J.  CHANON  G.  T.  LORANCE  N.  L.  SIMMONS 

L.  E.  CLARKE  W.  C.  MARCUS  W.  L.  THAYER 

Projection  Committee 

35-Mm  Programs 
R.  H.  MCCULLOUGH,  Chairman 
L.  R.  ABBOTT  W.  E.  GEBHARDT,  JR.  C.  R.  SAWYER 

B.  FREERICKS  W.  W.  LINDSAY,  JR.  W.  V.  WOLFE 

C.  R.  RUSSELL 
Officers  and  Members  of  I.A.T.S.E.  Locals  150  and  165 

16-Mm  Programs 

H.  W.  REMERSHIED,  Chairman 

A.  H.  BOLT  A.  M.  GUNDELFINGER 

C.  DUNNING  J.  RUNK 

Ladies  Reception  Committee 

MRS.  C.  W.  HANDLEY,  Hostess 

There  will  be  no  special  or  prearranged  ladies  entertainment  program  during 
the  five-day  1943  Fall  Conference.  However,  a  reception  parlor  will  be  available 
in  the  Hotel  where  the  ladies  may  meet  daily.  The  ladies  are  cordially  invited 
to  attend  the  functions  of  the  Conference. 

TENTATIVE  PROGRAM 

Monday,  October  18th 
9:30  a.m.     Hotel  Lobby;  Registration. 
The  program  for  the  morning  of  this  date  will  be  announced  later. 

12 :30  p.m.     Terrace  Room;  Informal  Get-Together  Luncheon  for  members,  their 
guests,  and  families.    The  luncheon  program  will  be  announced  later. 


Aug.,  1943]          FIFTY-FOURTH  SEMI-ANNUAL  CONFERENCE  197 

Due  to  the  hotel  labor  and  food  situation,  it  is  imperative  members  procure 
their  luncheon  and  dinner-dance  tickets  at  the  time  of  registering  so  that  the 
Arrangements  Committee  may  provide  the  necessary  accommodations. 

2 : 00  p.m.     Blossom  Room;  General  Session. 

8:00  p.m.     General  Session;  the  location  will  be  announced  later. 

Tuesday,  October  19th 

10:00  a.m.     Hotel  Lobby;  Registration.     Open  morning. 
2: 00  p.m.     Blossom  Room;  General  Session. 
8: 00  p.m.     General  Session;  the  location  will  be  announced  later. 

Wednesday,  October  20th 

9: 30  a.m.     Hotel  Lobby;  Registration. 
10:00  a.m.     Blossom  Room;  General  Session. 

2:00  p.m.     Open  afternoon  for  recreational  program  to  be  announced  later. 
8: 00  p.m.     Blossom  Room;   SMPE  Fifty-Fourth  Semi-Annual  Dinner-Dance. 
The  program  for  the  evening  will  be  announced  later.     ( Dancing  until 
12:30  a.m.;    strictly  informal  business  dress  and  uniforms  only.) 

Thursday,  October  21st 

10:00  a.m.     Open  morning. 
2: 00  p.m.     Blossom  Room;  General  Session. 
8:00  p.m.     General  Session;  the  location  will  be  announced  later. 

Friday,  October  22nd 

10: 00  a.m.  Blossom  Room;  General  Session. 
2: 00  p.m.  Blossom  Room;  General  Session. 
8:00  p.m.  Blossom  Room;  General  Session  and  Adjournment. 

Conference  Headquarters 

The  Pacific  Coast  Section  Officers  have  selected  the  Hollywood-Roosevelt 
Hotel,  Hollywood,  Calif.,  as  headquarters  for  the  1943  Fall  Technical  Conference 
with  the  following  per  diem  rates  guaranteed  by  the  hotel  management. 

Room  with  bath,  one  person $3.85 

Room,  double  bed,  with  bath,  two  persons 5.50 

Room,  twin  beds  with  bath,  two  persons 6.60 

Small  suite,  parlor,  bedroom  with  bath,  single  or  double  occupancy 8.80 

Room  reservation  cards  will  be  mailed  to  the  membership  early  in  September, 
and  should  be  returned  immediately  to  the  Hotel.  All  booked  accommodations 
will  be  guaranteed  when  confirmed  by  the  Hotel  Management.  Reservations 
are  subject  to  cancellation  at  any  time  prior  to  the  Conference. 

Indoor  and  outdoor  parking  facilities  will  be  available  at  the  Hotel  head- 
quarters if  desired. 


198  FIFTY-FOURTH  SEMI- ANNUAL  CONFERENCE 

The  Conference  registration  headquarters  will  be  located  in  the  Hotel  Lobby, 
and  members  and  guests  will  be  expected  to  register  and  receive  their  badges 
and  identification  cards.  The  registration  fees  are  used  to  help  defray  the 
Conference  expenses,  and  cooperation  in  tliis  respect  will  be  greatly  appreciated 
by  the  Local  Arrangements  Committee. 

The  identification  cards  will  provide  admittance  to  all  sessions  at  and  away 
from  the  Hotel.  They  will  be  honored  also  at  the  following  de  luxe  motion 
picture  theaters  on  Hollywood  Boulevard,  in  the  vicinity  of  the  Hotel:  Fox 
West  Coast  Grauman's  Chinese  and  Egyptian  Theaters,  Hollywood  Paramount, 
Hollywood  Pantages,  and  Warner's  Hollywood  Theater. 

Eastern  and  Mid-western  members  who  are  planning  to  attend  the  1943  Fall 
Conference  should  consult  their  local  railroad  passenger  agent  regarding  train 
schedules,  available  accommodations,  rates,  and  stop-over  privileges  en  route. 
If  a  San  Francisco  stop-over  is  included  in  the  trip  to  the  West  Coast,  the  Con- 
ference Committee  suggests  the  Mark  Hopkins  Hotel  on  "Nob  Hill."  Reserva- 
tions should  be  mailed  to  Mr.  R.  E.  Goldsworthy,  Assistant  Manager  of  the 
Mark  Hopkins. 

Note. — The  1943  Fall  Technical  Conference  is  subject  to  cancellation  if  later 
deemed  advisable  in  the  national  interest. 

W.  C.  KUNZMANN 

Convention  Vice-President 


IMPORTANT 

Hotel  reservation  cards  must  be  re- 
turned immediately.  Otherwise  the 
Hotel  cannot  guarantee  accommoda- 
tions. 


Members  intending  to  attend  the  Fifty-Fourth  Semi- Annual  Confer- 
ence should  make  arrangements  for  their  railroad  accommodations  im- 
mediately or  at  the  latest  one  and  a  half  months  in  advance  of  the  Con- 
ference date. 


SOCIETY  ANNOUNCEMENTS 


MAILING  OF  NOTICES  TO  MEMBERS  OF  THE 
ATLANTIC  COAST  SECTION 


As  the  territory  included  by  the  Atlantic  Coast  Section  of  the  Society  extends 
from  Maine  to  Florida  and  includes  the  Eastern  and  Central  Standard  Time 
zones  (as  the  result  of  the  discontinuance  of  the  Mid- West  Section),  many  of  the 
members  of  the  Section  find  it  impossible  to  attend  the  monthly  meetings  and 
other  functions.  The  situation  has  been  considerably  aggravated  by  the  present 
difficulties  of  transportation. 

For  these  reasons,  as  well  as  for  reasons  of  economy,  the  Board  of  Governors, 
at  the  meeting  held  on  May  3rd  at  New  York,  felt  that  notices  of  meetings, 
routine  letters,  and  other  material  should  be  sent  only  to  members  of  the  Section 
residing  in  the  New  York  metropolitan  area,  since  it  is  from  this  area  that  the 
meetings  draw  practically  all  their  attendance. 

However,  the  Board  provided  also  that  members  not  residing  in  the  New  York 
metropolitan  area  but  who  wish  to  receive  such  notices,  etc.,  may  have  their  names 
continued  upon  the  mailing  list  of  the  Section  by  writing  to  the  office  of  the 
Society,  at  the  Hotel  Pennsylvania,  New  York,  N.  Y. 


199 


MEMBERS   OF  THE  SOCIETY 

LOST  IN  THE  SERVICE  OF 

THEIR  COUNTRY 


FRANKLIN  C.  GILBERT 


ISRAEL  H.  TILLES 


JOURNAL  OF  THE  SOCIETY  OF 
MOTION   PICTURE   ENGINEERS 

VOLUME  XLI  •         •          •    SEPTEMBER,  1943 


CONTENTS 

PAGE 

Introduction  205 

Produced  by  the  United  States  Army  Signal  Corps 

H.  T.  DARRACOTT  206 

Some  Psychological  Factors  in  Training  Films 

M.  E.  GILLETTE  210 

Training  Film  Production  Problems          R.  P.  PRESNEL  215 

The  Service  Films  Division  of  the  Signal  Corps  Photo- 
graphic Center  E.  COHEN  222 

Animation  in  Training  Films  E.  SMITH  225 

Sound   Recording   at   the   Signal   Corps    Photographic 

Center  G.  C.  MISENER  226 

Field  Camera  Problems  R.  L.  RAMSEY  239 

Multiple-Film  Scene  Selector  H.  W.  LEASIM  246 

Film  Distribution  J.  D.  FINN  251 

Film  Utilization  B.  T.  WOLFF  255 

Fifty-Fourth  Semi- Annual  Technical  Conference  of  the 

Society,  Hollywood,  Calif.,  October  18-22,  1943  263 

Society  Announcements  269 
(The  Society  is  not  responsible  /or  statements  of  authors.) 


JOURNAL  OF  THE  SOCIETY  OF 
MOTION  PICTURE  ENGINEERS 

SYLVAN  HARRIS,  EDITOR 
ARTHUR  C.  DOWNES,  Chairman 

Board  of  Editors 

JOHN  I.  CRABTREE      ALFRED  N.  GOLDSMITH       EDWARD  W.  KELLOGG 
CLYDE  R.  KEITH       ALAN  M.  GUNDELFINGER     CHARLES  W.  HANDLE Y 

ARTHUR  C.  HARDY 
Officers  of  the  Society 
** President:  HERBERT  GRIFFIN, 

90  Gold  Street,  New  York,  N.  Y. 
** Past-President:  EMERY  HUSE, 

6706  Santa  Monica  Blvd.,  Hollywood,  Calif. 
** Executive  Vice-President:  LOREN  L.  RYDER, 
5451  Marathon  Street,  Hollywood,  Calif. 
*Engineering  Vice-President:  DONALD  E.  HYNDMAN, 

350  Madison  Avenue,  New  York,  N.  Y. 
** Editorial  Vice-President:  ARTHUR  C.  DOWNES, 

Box  6087,  Cleveland,  Ohio. 
* Financial  Vice-President:  ARTHUR  S.  DICKINSON, 

28  W.  44th  Street,  New  York,  N.  Y. 
**Convention  Vice-President:  WILLIAM  C.  KUNZMANN. 

Box  6087,  Cleveland,  Ohio. 
^Secretary:  E.  ALLAN  WILLIFORD, 

30  E.  42nd  Street,  New  York,  N.  Y. 
*Treasurer:  M.  R.  BOYER, 

350  Fifth  Ave.,  New  York,  N.  Y. 
Governors 

*H.  D.  BRADBURY,  411  Fifth  Avenue,  New  York,  N.  Y. 
*FRANK  E.  CARLSON,  Nela  Park,  Cleveland,  Ohio. 
*  ALFRED  N.  GOLDSMITH,  580  Fifth  Avenue,  New  York,  N.  Y. 
*A.  M.  GUNDELFINGER,  2800  S.  Olive  St.,  Burbank,  Calif. 
.  *CHARLES  W.  HANDLEY,  1960  W.  84th  Street,  Los  Angeles,  Calif. 
*EDWARD  M.  HONAN,  6601  Romaine  Street,  Hollywood,  Calif. 
*JOHN  A.  MAURER,  117  E.  24th  Street,  New  York,  N.  Y. 
**WILLIAM  A.  MUELLER,  Burbank,  Calif. 

**HOLLIS  W.  MOYSE,  6656  Santa  Monica  Blvd.,  Hollywood,  Calif. 
**H.  W.  REMERSHIED,  716  N.  La  Brea  St.,  Hollywood,  Calif. 
*  "JOSEPH  H.  SPRAY,  1277  E.  14th  Street,  Brooklyn,  N.  Y. 
**REEVE  O.  STROCK,  195  Broadway,  New  York,  N.  Y. 

*Term  expires  December  31,  1943. 
**Term  expires  December  31,  1944. 


Subscription  to  non-members,  $8.00  per  annum;  to  members,  $5.00  per  annum,  included 
in  their  annual  membership  dues;  single  copies,  $1.00.  A  discount  on  subscription  or  single 
copies  of  15  per  cent  is  allowed  to  accredited  agencies.  Order  from  the  Society  of  Motion 
Picture  Engineers,  Inc.,  20th  and  Northampton  Sts.,  Easton,  Pa.,  or  Hotel  Pennsylvania,  New 
York,  N.  Y. 

Published  monthly  at  Easton,  Pa.,  by  the  Society  of  Motion  Picture  Engineers. 

Publication  Office,  20th  &  Northampton  Sts.,  Easton,  Pa. 

General  and  Editorial  Office,  Hotel  Pennsylvania,  New  York,  N.  Y. 

Entered  as  second-class  matter  January  15,  1930,  at  the  Post  Office  at  Easton, 

Pa.,  under  the  Act  of  March  3,  1879.     Copyrighted,  1943,  by  the  Society  of  Motion 

Picture  Engineers,  Inc. 


SYMPOSIUM  ON  THE 
TRAINING  FILM  ACTIVITIES  OF  THE  U.  S.  ARMY 

Prepared  by  Members  of  the  U.  S.  Army  Signal  Corps,  Army  Service 

Forces,  and  Presented  at  the  Spring  Meeting  of  the  Society,  at  the 

Hotel  Pennsylvania,  New  York,  N.  Y.,  May  6,  1943 

The  papers  constituting  the  Symposium,  in  the  order  of  their  pub- 
lication in  this  issue  of  the  JOURNAL,  are  as  follows : 

"Produced  by  the  United  States  Army  Signal  Corps" ;  Capt.  Halvor  T.  Darracott, 

U.  S.  Army  Pictorial  Service,  Washington,  D.  C. 
"Some  Psychological  Factors  in  Training  Films";    Col.  M.  E.  Gillette,  U.  S. 

Army  Signal  Corps  Photographic  Center,  Astoria,  Long  Island,  N.  Y. 
"Training  Film  Production  Problems";   Lt.  Col.  Robert  P.  Presnel,  U.  S.  Army 

Signal  Corps  Photographic  Center,  Astoria,  Long  Island,  N.  Y. 
"The  Service  Films  Division  of  the  Signal  Corps  Photographic  Center";   Lt.  Col. 

Emanuel  Cohen,  U.  S.  Army  Photographic  Center,  Astoria,  Long  Island,  N.  Y. 
"Animation  in  Training  Films";    Major  Ellis  Smith,  U.  S.  Army  Signal  Corps 

Photographic  Center,  Astoria,  Long  Island,  N.  Y. 
"Sound  Recording  at  the  Signal  Corps  Photographic  Center";    Major  G.  C. 

Misener,  U.  S.  Army  Signal  Corps  Photographic  Center,  Astoria,  Long  Island, 

N.  Y. 

"Field  Camera  Problems";    Capt.  Ray  L.  Ramsey,  U.  S.  Signal  Corps  Photo- 
graphic Center,  Astoria,  Long  Island,  N.  Y. 
"Multiple  Film  Scene  Selector";    Capt.  Harry  W.  Leasim,  U.  S.  Army  Pictorial 

Service,  Washington,  D.  C. 
"Training  Film  Distribution";   Lt.  James  D.  Finn,  U.  S.  Army  Pictorial  Service, 

Washington,  D.  C. 
"Training  Film  Utilization";    Mr.  Boyd  T.  Wolff,  U.  S.  Army  Pictorial  Service, 

Washington,  D.  C. 


205 


PRODUCED  BY  THE  UNITED  STATES  ARMY  SIGNAL  CORPS 


CAPT.  HALVOR  T.  DARRACOTT* 


Through  the  Army  Pictorial  Service  the  Signal  Corps  serves  as 
teacher,  historian,  and  ambassador  for  the  United  States  Army. 
Day  by  day  demands  for  motion  pictures  of  the  combat  zones,  train- 
ing films,  film-strips,  English  versions  of  United  Nations  training  films, 
special  films  for  morale  purposes  are  growing  by  leaps  and  bounds. 

From  a  small  group  of  officers  and  civilians  and  two  training  film 
production  units,  the  Army  Pictorial  Service  has  grown  into  an 
organization  including  photographers  spread  throughout  the  world, 
as  well  as  a  major  studio  organization  for  the  production  of  training 
films.  The  range  of  activities  covered  by  this  organization  is  de- 
cidedly comprehensive,  including  a  good  many  contacts  that  are 
comparatively  little  known  to  the  general  public.  The  Army  profits 
greatly  by  the  thorough  cooperation  of  the  photographic  and  motion 
picture  industries  within  the  United  States. 

Proper  operation  of  this  far-flung  Army  Pictorial  Service  has  been 
planned  on  a  systematic  and  functional  basis.  The  Army  Pictorial 
Service  has  been  set  up  as  a  separate  service  within  the  Office  of  the 
Chief  Signal  Officer.  The  Chief  of  the  Army  Pictorial  Service  also 
is  a  member  of  the  Army  Pictorial  Board,  which  decides  which 
organization  within  the  three  main  divisions  of  our  modern  army — 
the  Army  Air  Forces,  the  Army  Service  Forces,  and  the  Army 
Ground  Forces — will  undertake  the  various  photographic  projects, 
and  who  will  be  responsible  for  their  completion  as  well  as  for  ob- 
taining the  necessary  trained  personnel  to  carry  out  those  projects. 
Three  branches  make  up  the  Army  Pictorial  Service:  the  Motion 
Picture  Production  Branch,  the  Pictorial  Administrative  Branch, 
and  the  Field  Activities  Branch.  Each  of  these  branches  in  turn 
has  several  sections,  the  numbers  and  functions  of  which  are  de- 
termined by  the  branch. 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  U.  S.  Army  Pictorial  Service,  Washington,  D.  C. 

206 


PRODUCED  BY  U.  S.  ARMY  SIGNAL  CORPS  207 

The  Motion  Picture  Production  Branch  is  responsible  for  the 
procurement  and  production  of  all  training  films  used  by  the  three 
divisions  of  the  Army.  The  Service  concerned  requests  from  the 
Chief  of  the  Army  Pictorial  Service  a  training  film  on  a  particular 
subject.  The  project  is  set  up,  the  "go  ahead"  signal  is  given,  and 
the  Motion  Picture  Production  Branch  decides  whether  or  not  the 
picture  is  to  be  produced  commercially  or  by  the  Signal  Corps 
facilities.  In  any  event,  by  whichever  method  used,  the  film,  in  its 
final  form,  is  viewed  by  the  Chief  of  the  Service  concerned,  and,  when 
given  his  approval,  is  handed  over  to  the  Training  Film  Distribution 
Section  for  distribution  and  proper  utilization  within  the  three 
divisions  of  the  Army. 

The  Motion  Picture  Production  Branch  also  is  responsible  for  the 
staff  supervision  of  the  procurement  of  film  bulletins,  film-strips, 
and  special  war  films  such  as  those  being  produced  by  the  834th 
Signal  Photographic  Detachment,  which  is  showing  the  background, 
history,  and  effect  of  the  present  world  conflict  upon  the  conquered 
nations.  Under  the  Special  Projects  Section  films  are  produced  at 
the  rate  of  at  least  one  per  month  for  distribution  to  the  war  workers 
of  the  United  States,  who  are  shown  how  their  particular  jobs  tie 
in  with  the  war  effort  and  what  important  parts  they  are  playing  in 
this  conflict.  Included  in  the  Army  Pictorial  Service  is  the  Combat 
Film  Section,  which  is  responsible  for  the  assembling  and  distribution 
to  the  Bureau  of  Public  Relations  of  the  War  Department  of  films 
exposed  by  the  motion  picture  photographers  of  the  Signal  Corps 
in  the  combat  zones.  Film  is  received  from  the  combat  zones,  de- 
veloped, printed,  viewed  by  the  photo  news  board  of  the  War  De- 
partment, and  classified  according  to  its  subject  matter;  and  that 
which  is  permissible  to  be  released  to  the  general  public  is  turned  over 
to  the  Bureau  of  Public  Relations  for  distribution  to  the  newsreel 
services.  This  service  is  provided  the  newsreel  companies  on  an 
exchange  basis.  Such  footage  as  is  shot  in  the  combat  zones  by  their 
own  photographers  as  is  needed  by  the  Signal  Corps  for  stock  shots 
is  turned  over  to  the  Signal  Corps  free  of  charge. 

A  special  development  laboratory  unit  known  as  the  Signal  Field 
Mobile  Laboratory  Unit  has  been  organized  to  go  into  the  theatre 
of  operations  and  carry  portable  35-mm  development  equipment. 
Taking  the  motion  picture  film  exposed  by  the  Signal  Corps  combat 
photographers  in  the  theater  of  operations,  this  unit  develops  it  and 
makes  a  print  for  the  Commanding  General  and  staff  of  that  theater 


208  CAPT.  H.  T.  DARRACOTT  [J.  S.  M.  P.  E. 

to  show  the  reaction  of  their  troops  to  the  present  situation  and  how 
their  work  can  be  improved.  Prints  of  these  films  will  be  returned  to 
the  United  States  to  the  Combat  Film  Section  for  distribution  to  the 
newsreel  companies  after  classification,  thus  shortening  the  period 
between  the  time  motion  picture  film  is  exposed  in  the  combat  zone 
and  the  time  it  is  received  in  the  United  States  for  dissemination 
through  the  newsreel  organizations. 

The  Field  Activities  Blanch  of  the  Army  Pictorial  Service  con- 
tains the  F-Mail  Section,  which  is  responsible  for  the  utilization  of 
microfilm  to  reduce  to  minute  dimensions  in  bulk  letters  to  and  from 
our  soldiers  in  the  combat  zones  overseas,  thus  speeding  up  the  news 
from  the  soldiers  in  the  field  to  their  loved  ones  at  home  or,  from 
those  at  home  to  the  soldiers  on  the  firing  line.  Avoiding  long  delays 
of  mail  sent  by  other  and  less  rapid  means,  this  service  contributes 
greatly  to  the  morale  of  both  the  troops  and  those  at  home.  The 
idea  of  this  type  of  service  originated  in  the  Franco-Prussian  War 
and  was  but  recently  revived.  The  modern  system  was  first  put 
into  effect  by  Airgraphs,  Ltd.,  which  established  microfilm  letters 
foi  the  British  troops. 

In  May  of  1942  the  Signal  Corps  contracted  for  a  similar  service 
to  be  established  for  American  troops  under  the  name  of  F-Mail. 
Shipment  of  F-Mail  letters  in  reduced  or  enlarged  form  is  handled  by 
the  American  Postal  Service  of  the  Adjutant  General's  office,  while 
the  reducing  to  microfilm  and  the  subsequent  enlargement  to  readable 
letters  is  done  by  personnel  of  the  Signal  Corps.  Far-flung  stations 
for  the  handling  of  the  service  have  been  set  up  in  areas  where  Ameri- 
can troops  are  stationed.  Close  cooperation  is  maintained  by  the 
Signal  Corps  with  the  British  Airgraph  Service,  and  arrangements 
have  been  made  for  F-Mail  Service  for  the  United  States  Navy  and 
Marine  Corps. 

Signal  Corps  motion  picture  photographers  use  standard  equip- 
ment, both  16-  and  35-mm,  and  cameras  of  standard  commercial 
design.  The  Army  Pictorial  Service  has  concentrated  its  efforts 
upon  modifying  the  equipment,  rather  than  designing  new  equipment 
to  make  it  mobile  and  easily  handled,  and  to  simplify  it  in  accordance 
with  Army  requirements.  The  Equipment  Section  of  the  Field 
Activities  Branch  has  been  responsible  for  the  development  and 
modification  of  standard  motion  picture  cameras  for  use  in  the  field. 

The  custodial  responsibilities  of  the  Army  Pictorial  Service  are 
centered  in  the  Still-Picture  Section  which  has  the  celebrated  motion 


Sept.,  1943]       PRODUCED  BY  U.  S.  ARMY  SIGNAL  CORPS  209 

pictures  and  the  still-picture  file  containing  thousands  of  films  shot 
during  the  First  World  War  as  well  as  famous  collections  of  still 
photographers,  such  as  Brady,  of  Civil  War  fame.  Close  cooperation 
with  the  United  Nations  Film  Committee,  especially  with  the 
British  and  Russian  photographic  Service,  has  resulted  in  the  ad- 
dition of  a  great  many  foreign  training  films  in  the  stock  of  the  Army. 
In  return,  American  training  films  are  being  made  available  to  others 
of  the  United  Nations.  Sound-tracks  in  the  appropriate  languages  are 
added  when  necessary. 


SOME  PSYCHOLOGICAL  FACTORS  IN  TRAINING  FILMS* 
COL.  M.  E.  GILLETTE** 

There  are  a  number  of  purely  psychological  factors  involved  in 
making  all  types  of  motion  pictures.  Several  of  these,  if  properly 
recognized  and  utilized,  prove  to  be  powerful  and  useful  tools  in 
making  training  films.  Five  of  the  most  important  of  these  factors 
will  be  briefly  discussed  in  this  paper. 

(1)  The  first  is  the  "defect"  in  human  vision  known  as  the  per- 
sistence of  vision.     This  effect  is  responsible  for  our  ability  to  see 
motion  pictures.     The  eye  retains  the  image  of  an  object  for  ap- 
proximately one- tenth  of  a  second  after  the  object  has  been  removed. 
The  removal  and  replacement  of  an  image  in  the  same  position  at  a 
rate  of  more  than  ten  times  per  second  is  seen  by  the  eye  as  a  single 
continuing   image.     In   sound-films    a   series   of   twenty-four   pro- 
gressive images,  or  still  pictures,  per  second  flash  upon  the  picture 
screen.     When   examined   individually   each   of   these   twenty-four 
pictures  is  a   "still"   picture.     If  they  are  examined  individually 
in  a  series,  they  show  a  progression  of  movement  of  the  objects  in 
gradually  changing  or  advancing  positions.     When  a  series  is  pro- 
jected upon  the  screen,  it  provides  an  illusion  of  motion.     Use  of  this 
principle  with  lifeless  objects  or  illustrations  makes  it  possible  to 
give  an  illusion  of  life  and  action  to  inanimate  things. 

(2)  The  second  factor  may  well  be  termed  "persistence  of  mental 
image"  as  distinguished  from  persistence  of  vision.     Extensive  use 
is  made  of  this  principle;  in  fact,  it  is  the  basis  of  story  telling  in  all 
modern  motion  pictures.     Motion  pictures  would  be  almost  im- 
possible or  at  least  extremely  unsatisfactory  if  producers  were  denied 
its  use,  as  production  costs  would  be  prohibitive.     It  is  the  principle 
of  connecting  a  number  of  scenes,  photographed  separately  and  at 
different  times  and  places,  into  a  continuity  thus  making  it  possible 
to  tell  a  story.     It  is  not  widely  understood  outside  motion  picture 
fields,  and  even  there  the  principle  is  not  often  expressed  but  is 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  U.  S.  Army  Signal  Corps  Photographic  Center,  Astoria,  Long  Island,  N.  Y. 
210 


PSYCHOLOGICAL  FACTORS  IN  TRAINING  FILMS  211 

rather  felt.  It  is  used  so  widely  and  in  so  many  different  ways  in 
film  production  that  a  full  discussion  of  it  would  be  beyond  the  scope 
of  this  paper. 

For  illustration,  when  a  film  producer  wishes  his  audience  to  identify 
the  action  as  taking  place  in  New  York  City,  he  will  flash  upon  the 
screen  a  general  view  of  the  skyline  of  lower  Manhattan,  a  view  of 
Brooklyn  Biidge,  The  Empire  State  Building,  Times  Square,  or  some 
other  well  known  landmark.  Following  this  scene  may  come  a  view 
of  some  side  street  (a  Hollywood  replica,  perhaps);  then  the  front 
of  a  house  (also  a  replica  or  a  miniature) ;  then  the  inside  of  a  living 
room  showing  four  persons  sitting  around  a  card  table  (a  Hollywood 
studio  scene);  then  a  front  view,  medium  close-up,  of  one  of  the 
players;  and  finally  a  close-up  or  an  insert  of  the  cards  in  the  hands 
of  a  player — perhaps  five  aces!  Individually,  these  scenes  may  have 
been  made  many  miles  apart,  at  different  times,  perhaps  a  year 
or  more  apart.  Yet  when  presented  in  a  film  the  aggregate  mental 
image  they  create  is  the  impression  that  the  time  is  the  present  and 
that  a  man  in  a  little  house  on  a  side  street  in  New  York  holds  five 
aces.  Thus  the  director  has  created  the  background  location  and 
opening  for  his  story,  which  persist  until  he  wishes  to  change  the 
locale  by  introducing  another  sequence  of  a  similar  nature. 

In  the  entertainment  film,  In  Old  Chicago,  extensive  use  was  made 
of  miniature  and  other  camera  trick  devices.  The  general  view  of 
burning  buildings  from  across  the  roof  tops  was  a  scene  of  a  mini- 
ature town  which  had  been  set  on  fire.  Street  scenes  were  made 
outdoors  on  the  studio  lot.  Views  of  the  action  inside  the  building 
were  made  on  the  studio  stage;  likewise,  the  close-up  action  of 
individuals  standing  against  the  sides  of  buildings  were  probably  of 
studio  origin.  Examined  individually  in  their  local  backgrounds, 
these  scenes  are  not  particularly  impressive,  but  examined  col- 
lectively after  assembly  by  expert  hands;  they  built  an  overall 
illusion  of  a  major  catastrophe,  taking  the  audience  into  intimate 
details  in  such  a  manner  that  the  audience  did  not  feel  any  dis- 
continuity or  break  in  the  overall  action  as  the  screen  images  rapidly 
shifted  from  exterior  to  interior  close-ups,  etc.  The  intermingling 
of  scenes  of  miniatures  and  scenes  of  full-size  figures  and  buildings 
was  performed  in  such  a  manner  as  to  obtain  the  overall  illusion 
of  reality,  and  the  audience  "saw"  the  people  in  the  midst  of  the  great 
fire.  The  persistence  of  the  mental  image  established  by  the  long 
shots  carries  through  the  showing  of  the  close-ups  and  medium  shots, 


212  COL.  M.  E.  GILLETTE  [j.  S.  M.  P.  E. 

and,  on  the  other  hand,  the  mental  images  of  the  close-up  action 
are  carried  over  into  the  long  views  in  the  minds  of  the  audience. 

The  interest-holding  qualities  and  audience-participation  in  the 
midst  of  the  action  is  wholly  dependent  upon  the  skillful  use  of  this 
principle  by  the  director  and  the  film  editors.  In  the  motion  picture 
industry  scenes  used  to  orient  the  audience  as  to  where  the  action 
is  taking  place  are  known  as  establishing  shots.  This  type  of  shot  is 
very  essential  in  instructional  training  films. 

(3)  The  third  factor  is  the  principle  of  motion.  A  feeling  of  power 
results  if  an  object  starts  at  the  center  of  the  screen  as  a  small  image 
in  the  distance  and  rapidly  approaches  dead  center  on  the  screen 
until  it  finally  fills  the  screen  completely.  When  an  object  fills  the 
screen  initially  and  rapidly  diminishes  in  size  into  the  distance,  a 
feeling  of  loss  of  power  or  relaxation  results.  Scenes  photographed 
at  a  very  low  angle  showing  rapidly  approaching  action  give  a  feeling 
of  power. 

A  feeling  of  smoothness  and  continuing  action  can  be  obtained 
by  using  a  series  of  scenes  in  which  the  movement  is  uniform  and 
steady,  and  always  in  the  same  direction.  The  nearer  the  movement 
to  the  horizontal  the  greater  is  the  effect. 

An  effect  of  greatly  increased  speed  and  excitement  may  result 
from  action  moving  across  the  screen ;  the  camera  follows  the  action 
and  the  backgrounds  appear  to  be  moving.  This  is  especially  true 
of  "pan"  shots.  For  example,  consider  scenes  showing  a  baby 
crawling,  a  man  walking,  a  man  on  a  bicycle,  a  man  on  a  galloping 
horse,  and  a  fast  airplane.  Arrange  the  scenes  in  the  order  named, 
starting  with  a  fairly  long  scene  of  the  baby  crawling,  and  progres- 
sively shorten  the  length  of  each  scene  with  the  airplane  scene  the 
shortest  in  the  series.  The  psychological  effect  is  that  of  acceleration. 
Deceleration  can  be  accomplished  by  the  reversal  of  the  example  just 
given. 

An  object  approaching  diagonally  down  from  a  corner  or  the  top 
of  the  screen  will  frequently  produce  the  feeling  that  the  action  is 
taking  place  on  a  slope  inclined  toward  the  observer.  This  effect 
results  from  placing  the  camera  high  and  tilting  it  downward.  Like- 
wise, an  object  coming  from  the  bottom  of  the  screen  and  moving 
upward  frequently  gives  a  feeling  that  the  object  is  climbing  a  slope. 
\When  the  camera  is  placed  on  the  top  of  a  hill  and  tilted  down- 
ward,fthe  action  will  appear  to  be  taking  place  on  level  ground. 
Likewise,  a  camera  placed  at  the  bottom  of  a  steep  hill  and  tilted  up- 


Sept. ,  1943  ]     PSYCHOLOGICAL  FACTORS  IN  TRAINING  FILMS  213 

ward  will  show  the  action  as  if  occurring  on  level  ground.  At  the 
top  of  the  hill  where  the  action  disappears  on  the  crest,  it  will  appear 
to  be  moving  down  hill.  A  side  position  for  the  camera  which 
profiles  the  action  and  the  hill  is  the  only  position  in  which  slope  can 
be  shown.  In  any  position  other  than  a  profiling  position,  the 
camera  definitely  flattens  the  terrain. 

A  series  of  very  short  scenes  or  a  composite  scene  showing  action 
moving  in  many  directions  gives  a  feeling  of  confusion.  Long 
scenes  from  the  same  viewpoint  produce  a  reaction  of  impatience  or 
slowness.  Inadequate  scene  length  in  successive  scenes  produces 
a  feeling  of  frustration  due  to  the  fact  that  the  audience  does  not  have 
an  opportunity  to  understand  what  is  occurring. 

(4)  The  fourth  psychlogical  factor  is  atmosphere.  The  lighting 
of  a  scene — the  brightness  or  lack  of  brightness,  or  the  mood 
established  through  the  placing  of  light,  and  the  use  of  light  and 
shadow  differences  in  the  scene — may  create  a  definite  reaction  in  an 
audience.  In  entertainment  films,  mystery  pictures,  for  example, 
are  usually  photographed  with  low  key  lighting  to  assist  in  creating 
an  illusion  of  mystery  and  the  unknown.  Comedies  are  generally 
photographed  in  high  key;  the  scenes  are  bright  and  clear  to  assist 
in  creating  an  illusion  of  lightness.  Deep,  murky  shadows  across 
a  scene  can  be  used  to  obtain  a  reaction  of  depression  or  suspense.  A 
flat,  muddy  appearing  scene  made  under  rainy  or  dark  light  con- 
ditions gives  a  depression  reaction. 

Another  factor  is  the  environment  or  the  surroundings  of  the 
center  of  action.  Obviously,  a  refuse  dump  or  paper-littered  drill 
field  has  no  place  in  the  background  of  a  film  showing  snappy  drill. 
Incongruous  backgrounds  destroy  the  effect  and  validity  of  a  scene. 
A  shot  simulating  battle  conditions  made  on  the  parade  ground,  for 
example,  is  greatly  weakened  if  barracks  show  in  the  background. 
Likewise,  a  group  of  spectators  or  automobile  traffic  in  the  back- 
ground will  effect  the  same  result. 

Natural  sound  recordings  can  be  used  to  supplement  or  reinforce 
the  emotional  reaction  of  a  scene.  When  so  used  they  become  part 
of  the  ' 'atmosphere"  of  the  scene.  On  the  other  hand,  incongruous 
sounds  may  seriously  mar  or  destroy  the  desired  effect  or  validity 
of  a  scene.  Twittering  birds,  distant  laughing,  a  train  whistle,  and 
similar  sounds  may  mar  the  desired  effect.  The  lowing  of  cattle  at 
the  instant  a  platoon  leader  commands  "charge"  will  completely 
destroy  the  effect  desired  and  turn  a  serious  situation  into  a  comedy. 


214  COL.  M.  E.  GILLETTE 

(5)  The  fifth  factor  is  the  principle  of  comparison.  In  the  enter- 
tainment field,  in  order  to  bring  about  the  desired  emotional  effect, 
it  is  common  practice  to  alternate  pathos  and  comedy  as  relief 
mediums.  In  training  film  it  is  deadening  and  interest-destroying 
to  hammer  continually  on  "do  this,"  "do  that,"  etc.,  without  pro- 
viding some  means  of  relieving  the  tension  of  the  audience.  I 
do  not,  however,  mean  to  infer  that  we  should  inject  comedy  or 
pathos  as  relief  mediums  into  training  films. 

There  are  many  ways  of  using  this  principle  of  comparison  in  the 
production  of  training  films  although  they  are  not  as  obvious  as 
the  above  examples.  There  are  several  methods  of  obtaining  this 
relief  without  injecting  irrelevant  or  distracting  factors  into  a  film. 
In  a  film  that  is  basically  a  "what"  or  a  "how"  type  of  film,  we  are 
often  able  to  inject  a  little  of  the  "why"  into  the  film  to  relieve  tension 
and  as  an  interest-arousing  and  a  holding  factor.  The  use  of  objects 
or  ideas  close  to  common  experience  may  often  be  properly  used 
to  draw  comparison  and  illustrate  something  otherwise  abstract  and 
thus  relieve  tension. 

In  films  showing  the  duties  of  a  gun  crew  in  placing  and  serving 
the  gun,  relief  can  be  provided  by  showing  the  result  of  such  firing. 
In  some  types  of  films  the  nature  of  the  action  itself  provides  the 
necessary  relief  through  the  shifting  of  background  situations  or  of 
action.  While  such  relief  is  desirable  and  necessary,  it  is  difficult 
to  prescribe  a  definite  formula  as  to  its  use,  or  to  provide  it  without 
introducing  undesirable  factors.  The  use  of  this  principle  requires 
considerable  thought  during  the  planning  and  production  stages, 
and  wherever  it  can  be  used  effectively  with  no  undesirable  results, 
it  should  be  so  used. 

It  may  be  safely  said  that  sound-films  can  be  used  to  arouse  and 
influence  all  the  human  emotions,  in  practically  the  same  way  that 
similar  real-life  situations  would  influence  an  individual.  The 
settings  and  lighting  may  depress  or  raise  the  spirits;  movement  on 
the  screen  may  thrill  or  frighten;  scene  selection  may  transport  us 
into  distant  lands  or  into  the  past.  Any  of  our  numerous  emotions 
may  be  played  upon  by  suitable  scene  action,  scene  selection,  light- 
ing, sound,  etc.  A  complete  discussion  of  these  factors  is  impossible 
here.  The  examples  mentioned  should,  however,  indicate  that  this  is 
a  very  broad  and  important  field,  and  an  understanding  of  the  prin- 
ciples is  necessary  so  that  we  may  avoid  introducing  undesirable  or 
unwanted  reactions  while  striving  to  create  those  that  are  desirable. 


TRAINING  FILM   PRODUCTION  PROBLEMS* 
LT.  COL.  R.  P.  PRESNEL** 


In  the  Army,  in  the  production  of  training  films,  we  have  a  special 
phenomenon,  and  that  is  the  making  of  motion  pictures  without 
artistic  temperament.  I  think  it  is  something  new  under  the  sun. 

They  say  that  war  is  a  great  leveller.  You  never  hear  an  Army 
picture  director  raise  his  voice  and  shout  or  complain  because  every- 
thing is  not  exactly  as  he  wishes  it.  Our  camera  units  are  also  groups 
in  which  many  sentences  begin  and  end  with  the  word  Sir.  We  are 
fighting  the  war  with  scenarios,  using  words  for  ammunition.  We 
have  90-mm  adjectives,  155-mm  verbs,  40-mm  automatic  nouns. 
And  our  theme  song  is,  "Praise  the  Lord — and  Parse  the  Ammuni- 
tion." Our  cameramen  are  mostly  sergeants  and  our  assistant 
directors  are  often  corporals.  They  may  carry  gas  masks  and  eat 
out  of  mess  kits.  They  may  drill  mornings  and  nights  to  be  ready. 
This  is  a  new  kind  of  motion  picture  making. 

Training  film  production  is  the  assembling  of  film  into  sequences 
that  will  teach  military  subjects  to  large  audiences  of  average  intel- 
ligence. All  training  films  are  aimed  at  the  soldier  in  combat,  or  at 
least  in  the  theater  of  operations,  and  are  designed  to  teach  him  the 
use  of  his  weapons,  his  equipment,  the  care  of  his  health,  and  certain 
principles  of  tactics  and  individual  care.  For  this  reason,  the  close-up 
is  used  to  the  best  advantage.  In  a  sense  the  films  are  educational 
films,  but  with  a  different  accent.  The  accent  is  speed  and  the  ever- 
present  reminder  of  danger.  We  have  to  put  our  message  across 
with  a  sharp  impact.  That  is  one  reason  why  we  are  in  the  Signal 
Corps :  we  have  a  message  to  deliver. 

Most  of  the  Army  training  films  are  made  in  the  field,  by  which 
we  mean  camps  and  Army  schools  scattered  throughout  the  country. 
In  Astoria  we  have  a  large  and  excellent  studio,  an  historic  studio,  of 
which  we  are  very  proud,  but  only  a  small  percentage  of  our  pictures 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
!*  U.  S.  Army  Signal  Corps  Photographic  Center,  Astoria,  Long  Island,  N.  Y. 

215 


216  LT.  COL.  R.  P.  PRESNEL  [j.  s.  M.  P.  E. 

can  be  taken  indoors,  on  our  stages.  We  can't  maneuver  tanks  or 
lay  down  an  artillery  barrage,  or  stage  cavalry  movements  anywhere 
but  out  in  the  desert,  or  range,  or  on  practice  grounds. 

Our  crews  travel  in  camera  trucks.  We  have  done  some  experi- 
menting in  the  building  of  these  camera  trucks,  for  compactness  and 
economy  of  space,  and  camera  equipment  comes  under  the  category 
of  delicate  instruments.  The  equipment  must  be  carefully  packed, 
cleaned,  and  cared  for  in  the  field  so  that  it  will  continue  to  function. 
There  are  some  fifteen  or  sixteen  camera  crews  ranged  across  the 
country  right  now,  and  this  represents  a  quarter  of  a  million  dollars 
worth  of  equipment  that  must  be  transported  and  taken  care  of. 
This  is  quite  an  item  and  quite  a  responsibility.  It  becomes  even 
more  complicated  when  sound  equipment  is  added,  all  of  which  must 
also  be  transported  and  maintained. 

We  can  not  and  do  not  send  out  great  caravans  to  install  set-ups 
for  shooting  outdoors.  The  average  camera  unit  consists  of  five  to 
seven  men  with  an  officer  in  charge.  Officer,  sergeant,  privates, 
all  bear  responsibility.  They  must  constantly  improvise  and  meet 
the  most  unexpected  events  with  American  ingenuity,  just  as  men 
in  fox-holes  and  men  in  tanks  are  doing. 

That  is  why  we  have  no  time  for  temperament.  All  have  to  work 
together.  Working  in  the  field,  often  under  the  most  adverse  con- 
ditions of  weather  and  equipment,  our  camera  units  carry  out  the 
dictum  of  that  famous  general  on  Bataan:  "We  must  make  the  most 
of  the  little  we  have." 

I  do  not  mean  to  imply  that  the  Army  does  not  give  its  crews  the 
best  equipment  available,  but  rather  that  not  too  much  is  available 
anywhere  these  days,  as  you  well  know.  A  Signal  Corps  Camera 
Unit  may  be  one  in  which  a  first  cameraman — we  do  not  have  nearly 
enough  of  them — will  also  be  his  own  operator  and  very  often  carry 
his  own  camera.  Our  directors  do  not  have  chairs  with  their  names 
painted  on  them,  and  our  script  clerk  very  often  is  a  utility  man  or 
assistant  director  to  boot.  He  will  take  notes  with  one  hand  and 
carry  a  battery  with  the  other. 

In  the  field,  our  crews  can  not  sit  by  waiting  for  the  right  weather 
or  for  light  of  exactly  the  correct  quality.  Colonel  Gillette  has  given 
us  a  motto,  "One  training  film  on  the  screen  today  is  worth  ten  on 
the  screen  next  year."  We  have  no  time  to  lose — not  a  minute. 

Our  job  is  to  teach  men  how  best  to  protect  themselves  and  carry 
out  their  duties  in  the  face  of  peril.  That  means  that  photographic 


Sept.,  1943]  PRODUCTION  PROBLEMS  217 

excellence  is  not  a  prime  consideration.  And  yet,  we  know  that  the 
best  training  films  are  those  that  are  the  best  photographed  and 
directed.  If  we  want  to  teach  other  men  to  do  their  jobs  well,  we 
must  demonstrate  to  them  that  we  too  are  doing  our  jobs  well. 
And,  of  course,  we  have  a  critical  audience;  our  training  film  must 
compete  for  attention  or  admiring  respect  with  the  entertainment 
films  that  are  shown  nightly  in  the  same  camp.  It  may  be  said  that 
what  we  have  here  is  the  problem  of  turning  out  pictures  comparable 
in  skill  and  finish  with  the  best  modern  products  of  Hollywood,  under 
conditions  that  in  many  ways  compare  to  those  that  prevailed  in  the 
days  of  the  motion  picture's  infancy. 

This  fact,  that  we  are  getting  back  to  essentials  in  this  work  of  ours, 
is  perhaps  the  most  outstanding.  War  is  always  a  matter  of  getting 
back  to  essentials.  So,  in  organizing  our  work  and  in  training  the 
men  who  are  to  make  the  training  films,  we  have  undergone  a  process 
of  unlearning  and  reeducation  for  ourselves. 

Many  of  the  men  in  our  units  enjoyed  reputation  and  success  as 
writers  and  technicians  in  civilian  life.  They  have  come  to  us  with 
complete  knowledge  of  how  to  make  pictures  "the  Hollywood  way," 
but  in  the  Army  we  are  up  against  something  different.  The  main 
idea  in  Hollywood  technique  is  to  entertain.  When  these  same  men 
write  and  shoot  training  films,  their  purpose  is  to  teach.  It  is  a 
different  approach. 

Obviously,  the  appeal  of  the  training  film  is  not  to  the  emotions  or 
even  to  the  imagination,  but  to  the  mind.  The  training  film  must 
be  written  in  simple  language,  so  simple  that  any  soldier  may  grasp 
its  teaching.  It  must  move  quickly,  yet  must  make  its  point  very 
thoroughly  without  seeming  repetitious.  Men  brought  in  to  view 
these  films  may  have  spent  hours  marching  or  carrying  out  fatiguing 
duties.  They  may  not  always  be  as  alert  and  attentive  as  they 
might  otherwise  be.  The  pictures  may  have  to  be  shown  more  than 
once,  and  so  they  must  not  include  scenes  or  speeches  that  on  an- 
other showing  will  lose  their  original  effect.  For  example,  when  we 
sought  to  lighten  our  films  by  the  use  of  humor,  we  soon  discovered 
that  the  jokes  or  gags  did  not  "go  over"  very  well  the  second  time 
and  third  time.  Similarly,  suspense  is  not  a  very  useful  device  for 
us.  How  to  keep  our  films  lively,  how  to  bid  for  attention,  and  how 
to  hold  it,  in  the  face  of  such  restrictions — that  is  what  our  writers 
and  directors  are  up  against.  How  to  climb  a  telephone  pole,  how 
to  splice  a  wire,  how  to  build  a  ponton  bridge  under  fire,  how  to  clean 


218  LT.  COL.  R.  P.  PRESNEL  [J.  S.  M.  P.  E. 

a  gun,  how  to  avoid  malaria,  how  to  keep  your  feet  clean — it  does  not 
sound  like  very  interesting  material,  does  it?  But  it  is,  and  it  is 
important  that  men  know  these  things.  Their  lives  depend  upon  it. 

We  give  special  orientation  courses  to  our  writers,  designed  to 
initiate  them  into  the  secrets  of  good  teaching.  We  have  lectures 
by  psychologists  who  have  studied  the  best  methods  and  principles. 
It  is  not  easy  to  stir  or  delight  an  audience  with  an  exposition  of  how 
an  anti-aircraft  gun  is  put  together.  Yet  that  is  a  fundamental  part 
of  our  job.  We  call  such  pictures  "nut-and-bolt"  pictures.  Given 
the  job  of  telling  about  the  bolt  mechanism  of  the  M-l  rifle,  our 
writer  has  no  opportunity  to  wax  lyrical.  But  if  the  subject  is  thor- 
oughly understood  by  the  writer  and  is  well  organized  by  him,  its 
exposition  will  be  clear  and  interesting  to  the  man  who  is  to  use  the 
rifle  and  who  appreciates  how  much  depends  upon  his  knowing  how 
to  fire  it. 

The  scenario  is  especially  important,  and  strict  adherence  to  it  is 
one  of  our  production  problems.  We  can  not,  as  so  often  happens  in 
Hollywood,  rewrite  our  stories  on  the  spot.  We  can  not  stop  our 
shooting  for  story  conferences.  The  branch  of  service  for  which 
we  are  working  has  given  us  a  story,  and  we  stick  to  it.  That  is 
because  every  line,  every  scene,  every  detail  presented  in  our  film 
has  been  carefully  gone  over  and  approved  by  experts.  To  make 
changes  in  the  scenario  would  mean  to  go  back  through  channels 
for  approval.  The  fullest  cooperation  exists  between  the  branches 
and  us  in  the  preparation  of  the  scenarios — and  we  stick  to  the  tech- 
nical content  because  it  represents  the  best  thought  of  the  Army  on 
the  subject. 

Our  writers  travel  to  the  service  schools  and  often  take  courses  in 
the  subjects  about  which  they  are  to  write.  They  accompany  troops 
on  maneuvers,  they  watch  experiments,  they  learn  at  firsthand,  so 
that  they  can  teach  vividly  and  accurately.  Technical  advisers, 
men  highly  schooled  in  specific  subjects,  are  always  at  hand.  The 
writing  of  a  training  film  is  a  matter  of  teamwork — hard,  pains- 
taking teamwork. 

We  thus  observe  our  writers  working  side  by  side  with  military 
experts  on  poison  gases,  bombs,  tanks,  weapons  of  every  kind.  It 
has  been  one  of  the  tasks  of  our  writers,  who  speak  the  language  of 
motion  pictures  in  all  its  technical  terms  that  sound  so  mysterious 
to  outsiders,  to  put  across  their  ideas  to  these  men  who  are  specialists 
in  the  various  phases  of  military  activity.  We  are  frequently  asked 


Sept.,  1943]  PRODUCTION  PROBLEMS  219 

to  supply  these  technical  advisers  with  a  glossary  of  what  is  meant 
by  "dolly  shots,"  "pans,"  "wipes,"  and  "dissolves." 

Recently  a  military  adviser  suggested  that  a  certain  scenario  sub- 
mitted to  him  was,  in  his  words,  "pretty  rugged,"  because  he  read 
so  many  directions  calling  for  "shooting  from  the  rear,"  "shooting 
from  above,"  and  thought  we  meant  shooting  with  bullets  rather 
than  with  film.  He  was  considerably  relieved  when  we  explained 
that  we  did  not  intend  to  wipe  out  half  the  men  assigned  to  us  as 
actors.  A  very  friendly  and  intelligent  technical  adviser  not  used  to 
Hollywood  talk,  obligingly  brought  forth  a  T-square  when  the 
writer  informed  him  that  he  would  like  another  angle  on  a  script. 

We  have  succeeded,  nonetheless.  Indeed,  sometimes  we  are  so 
successful  in  winning  over  and  educating  these  technical  advisers  in 
matters  that  have  to  do  with  the  making  of  motion  pictures,  that  we 
find  ourselves  with  another  problem  on  our  hands :  technical  advisers 
succumb  to  the  widespread  temptation  and  wish  to  become  motion 
picture  producers  themselves.  This  calls  for  the  utmost  tact  on  the 
part  of  those  assigned  to  work  with  them  for  the  temptation  gets 
into  the  blood  stream  sometimes  and  the  technical  adviser  becomes 
a  very  sick  man. 

In  our  films  the  organization  of  material  is  not  our  only  problem. 
If  Hollywood  has  a  language  of  its  own,  so  has  the  Army.  We  have 
had  to  learn  how  to  speak  Army  language  and  also  how  to  make  Army 
language  clear  to  our  civilian  soldiers.  Much  of  the  material  we  have 
put  on  film  has  already  been  set  down  in  field  manuals.  The  lan- 
guage of  these  manuals  is  very  precise,  but  when  read  aloud  it  does 
not  make  the  most  interesting  kind  of  narration.  It  "talks  like  a 
book."  We  have  to  tackle  the  job  of  translating  this  most  formal 
and  precise  field  manual  language  into  everyday  speech  that  will 
make  the  point  more  effectively  and  still  be  correct.  Our  films  must 
be  "racy"  in  speech  and  still  have  dignity,  because  they  speak  with 
the  impersonal  voice  of  the  United  States  Army,  whether  our  narrator 
is  a  tough  old  sergeant  or  a  brigadier  general. 

The  shooting  of  a  training  film  is  even  more  a  matter  of  teamwork. 
It  begins  with  preparations  and  explorations  in  which  we  try  to  fore- 
see just  what  our  crews  will  need  or  have  to  contend  with  from  the 
moment  they  leave  the  post  until  the  last  foot  of  film  is  shot.  It  is 
like  planning  a  campaign  in  miniature. 

In  order  to  obtain  our  actors,  and,  even  more  important,  in  order 
to  obtain  the  military  materiel — the  tanks,  the  planes,  the  motor 


220  Lx.  COL.  R.  P.  PRESNEL  [j.  S.  M.  P.  E. 

vehicles,  the  guns,  the  jeeps,  ammunition,  chemicals — that  we  re- 
quire when  filming  a  picture,  we  must  initiate  requests  through  the 
appropriate  channels.  I  need  hardly  tell  you  that  we  do  not  have 
idle  tanks  and  idle  guns  and  idle  men  standing  around  and  waiting 
for  us.  Every  gun,  every  tank,  every  man  is  busy;  it  is  not  easy 
for  us  to  obtain  their  services,  and  when  we  do  get  them,  we  have  to 
make  efficient  use  of  them  without  any  loss  of  time.  If  we  have  been 
given  use  of  a  company  of  men  today,  we  can  not  send  them  back 
because  the  sky  is  cloudy,  and  expect  them  on  hand  tomorrow. 
They  may  be  scheduled  for  maneuvers  tomorrow,  and  today's  cast 
may  be  on  its  way  overseas  before  the  month  is  out.  That  means 
that  if  retakes  are  needed,  that  will  not  be  a  simple  matter  either. 
We  have  to  shoot  right  the  first  time;  the  same  rule  that  applies  for 
the  infantry  man  aiming  his  gun  at  the  enemy  applies  to  us  also. 

We  have  found  it  the  best  policy  to  use  soldiers  from  the  ranks  as 
our  actors,  so  that  the  men  who  see  the  pictures  will  most  readily 
identify  themselves  with  the  men  on  the  screen.  We  do  not  use  the 
handsomest  soldiers,  or  the  trimmest,  or  the  most  stalwart  or  intelli- 
gent looking  soldiers,  but  ordinary  men  of  all  racial  types.  We 
were  considerably  embarrassed,  however,  on  one  occasion,  when  one 
of  the  southwestern  camps  supplied  us  with  a  contingent  of  Japanese- 
American  soldiers  to  enact  an  important  scene.  They  were  fine 
fellows  and  good  soldiers  and  loyal  to  everything  American,  but  we 
did  not  know  how  the  rest  of  the  Army  would  take  instruction  from 
them.  It  happened  to  be  a  scene  in  which  poison  gas  was  depicted, 
however,  and  so  we  were  able  to  put  them  ah1  in  gas  masks  and 
get  away  with  it.  When  these  man  had  their  masks  on,  we  had  no 
trouble  with  them  in  the  matter  of  their  stealing  side  glances  toward 
the  camera,  but  elsewhere  we  constantly  have  to  work  with  camera- 
shy  actors.  Nevertheless,  we  think  it  worth  while  to  use  ordinary 
soldiers.  These  are  pictures  by  soldiers,  with  soldiers,  for  soldiers. 

It  is  not  only  the  camera  field  units  that  have  special  problems. 
Our  sound  units  have  even  greater  difficulty,  especially  since  planes 
are  so  likely  to  be  flying  over  the  camps  where  our  films  are  being 
made.  One  director  said  to  me,  "If  it  isn't  a  plane,  it's  a  train;  and 
if  it  isn't  a  train,  it's  artillery  on  the  range  or  target  practice — and  if 
if  isn't  target  practice,  it's  crickets,  and  the  damn  crickets  never 
stop!" 

We  have  been  short  of  such  mobile  sound  units  but  their  number 
has  been  increasing,  and  more  and  more  we  are  being  able  to  use 


Sept.,  1943]  PRODUCTION  PROBLEMS  221 

live  sound  to   the  heightened  effectiveness  of  our  film   teaching. 

This  is  a  war  of  rapid  change,  of  learning  by  experience.  Pro- 
cedures, weapons  may  change  overnight,  and  we  may  find  ourselves 
with  a  picture  half  finished  and  suddenly  obsolete.  Our  films  must 
be  correct  in  every  detail.  We  can  not  teach  men  methods  that  have 
been  disapproved.  You  may  be  able  to  cover  up  a  mistake  in  a 
historical  picture  in  Hollywood.  But  we  can  not  cover  up  anything. 
We  must  not  make  any  mistakes.  So  we  are  frequently  forced  to 
very  complicated  expedients  in  order  to  save  our  films  and  keep  them 
abreast  of  changes.  We  are  in  a  race  against  time,  but  so  is  the 
whole  Army,  and  we  are  only  trying  to  keep  up.  The  faster  we  make 
our  pictures,  the  quicker  our  millions  of  men  will  be  brought  up  to 
date  in  their  training,  ready  for  the  task  we  all  face. 

Another  aspect  of  our  work  is  psychological  preconditioning  for 
battle.  So  far  as  possible,  we  try  to  simulate  actual  combat  con- 
ditions and  show  the  men  that  what  they  are  learning  in  the  camps 
will  be  applied  in  the  moments  of  stress  and  crisis  that  await  them. 
It  is  not  the  chief  function  of  training  films  to  be  inspirational;  they 
are  not  meant  for  propaganda,  yet  this  element  is  not  lacking  al- 
together. We  not  only  show  men  how  to  use  weapons,  but  we  sug- 
gest to  them  the  urgency  of  their  knowing  how  to  conduct  themselves 
properly  with  them.  Among  the  training  films  we  have  made  is  a 
series  for  the  Army  Ground  Forces  in  which  various  psychological 
problems  that  have  to  deal  with  fear  in  battle,  and  discipline,  have 
been  dramatically  presented.  I  am  proud  to  say  that  these  films  have 
won  commendation  from  the  War  Department  who  told  us  that  they 
considered  them  worth  ten  divisions  to  our  Army. 


THE  SERVICE  FILMS  DIVISION  OF  THE  SIGNAL  CORPS 
PHOTOGRAPHIC  CENTER* 


LT.  COL.  EMANUEL  COHEN** 

The  subject  of  this  paper  concerns  a  little  known  but  rapidly 
expanding  activity  of  the  Signal  Corps  Photographic  Center — the 
Service  Films  Division.  The  name  Service  Films,  derived  from  the 
functional  nature  of  the  special  films  produced,  best  describes  the 
type  of  motion  pictures  that  are  designed  to  provide  a  special  service 
to  the  Army  at  large. 

The  Service  Films  Division  was  organized  to  consolidate  all  film 
activities  which  by  their  special  nature  could  be  classified  as  "service" 
and  not  "training"  films.  To  distinguish  between  the  two  is  difficult 
because  it  is  hard  to  say  that  service  films  do  not  train,  because  they 
do;  but  their  primary  function  is  to  disseminate  information  through 
the  medium  of  motion  pictures  more  effectively  than  through  printed 
pamphlets  and  mimeographed  letters. 

Modern  mechanized  war  changes  so  swiftly  and  new  equipment  is 
developed  so  rapidly  that  a  film  service  equally  as  flexible  was  needed 
to  transmit,  visually,  data  on  new  weapons,  equipment,  and  tech- 
niques to  branches  of  the  Army  that  could  utilize  the  information  to 
best  advantage.  Since  training  films  are  based  upon  doctrines 
developed  over  a  long  period  of  time,  service  films  are  designed  to 
disseminate  quickly  new  doctrines  to  Staff  Officers  whose  task  it  is  to 
evaluate  every  piece  of  new  equipment  and  fighting  technique  and 
decide  in  the  shortest  possible  time  what  equipment  and  methods 
are  to  be  adopted  by  our  fighting  forces.  Distribution  of  these 
service  films  is  not  limited  to  this  country  but  is  extended  overseas 
for  the  information  of  officers  and  men  in  combat  areas.  Some 
service  films  show  the  various  types,  capabilities,  and  effectiveness 
of  the  enemy's  weapons.  Prints  of  this  type  of  technical  reel  would 
be  distributed  to  advanced  echelons  in  combat  zones  as  well  as  to 
ordnance  officers  in  this  country.  By  this  means  troops  overseas, 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  U.  S.  Army  Signal  Corps  Photographic  Center,  Astoria,  Long  Island,  N.  Y. 
222 


SERVICE  FILMS  DIVISION  223 

soon  to  face  the  enemy,  are  given  a  realistic  demonstration  of  the  latest 
types  of  weapons  the  enemy  uses.  Applying  here  the  theory  that  he 
who  is  forewarned  is  forearmed,  our  officers  and  non-coms  can  use 
this  information  to  devise  defenses  against  these  weapons  and  also  to 
reduce  the  effect  of  shock  encountered  by  troops  who  would  have 
had  to  face  a  type  of  fire  that  they  had  no  idea  the  enemy  possessed. 

For  some  time,  high-ranking  officers  of  the  Army  Ground  Forces 
and  the  Army  Service  Forces  had  been  considering  ways  and  means 
of  improving  the  use  of  chemical  mortars — small  cannons  that  fire 
smoke  and  other  chemical  shells.  The  officers  were  not  satisfied 
with  the  number  of  men  and  pieces  of  equipment  that  were  required 
to  blanket  an  area  with  a  smoke  or  gas  screen.  Numerous  combina- 
tions were  discussed  pro  and  con  and  tested.  Finally,  the  'Tour- 
Point-Two  Chemical  Mortar,"  with  its  small  complement  of  men 
and  machines,  looked  most  promising,  so  it  was  tested,  not  before  a 
group  of  assembled  staff  officers  on  leave  from  their  official  duties, 
but  before  motion  picture  camera  crews  with  their  Eyemos  and 
Mitchells  which  photographed  every  detail  of  the  test  far  better 
than  individuals  could  observe  at  firsthand  with  the  naked  eye.  Not 
only  was  much  time  saved  for  a  score  or  more  of  the  Army's  leading 
ordnance,  chemical  warfare,  tactical,  and  other  experts,  but  at  the 
same  time  a  permanent  record  was  made  that  could  be  studied  and 
restudied.  This  film  also  eliminated  the  necessity  for  restaging  the 
tests  at  additional  expense  for  those  who  could  not  attend  because 
of  the  pressure  of  more  important  duties.  As  a  result,  the  Army's 
eventual  adoption  of  the  Four-Point-Two  Chemical  Mortar  was  in 
no  small  part  due  to  the  film  demonstration,  which  forms  part  of 
what  is  known  as  Film  Bulletin  No.  46. 

Other  bulletins  and  special  productions  made  by  the  Service  Films 
Division  have  included  such  subjects  as  "Battle  Firing."  This  bul- 
letin showed  our  men  a  new  and  revolutionary  technique  of  firing 
small  arms.  To  date  a  large  number  of  analytical  tests  have  been 
photographed  for  the  various  service  boards  of  the  Army  such  as  the 
Ordnance  Board  at  Aberdeen  Proving  Ground,  where  new  types  of 
American,  allied,  and  enemy  guns,  bombs,  armor-plate,  jeeps,  and 
trucks  undergo  continuous  tests  to  develop  the  best  arms  and  equip- 
ment for  America's  armed  forces.  Camera  teams  ate  stationed  at 
these  boards  to  make  the  tests  when  ordered.  The  commentaries 
of  these  bulletins  stress  the  significance  of  the  various  scenes  as  they 
apply  to  training.  Errors  as  well  as  proper  procedure  are  pointed 
out  in  the  narration. 


224  LT.  COL.  E.  COHEN 

Another  activity  of  the  Service  Films  Division  is  the  Special 
Productions  Branch.  This  unit  makes  special  films  ordered  by, 
for  example,  the  Secretary  of  War,  who  may  request  a  film  on  the 
manpower  resources  of  the  United  States;  the  Chief  Signal  Officer, 
who  may  wish  to  present  a  film  report  on  the  activities  of  the  Signal 
Corps;  or  the  Commanding  General  of  the  Army  Service  Forces, 
who  may  order  a  film  made  to  demonstrate  the  huge  supply  problem 
involved  in  equipping  and  transporting  America's  first  AEF  to 
North  Africa.  These  pictures  are  made  within  a  given  time  limit, 
mostly  from  the  extensive  resources  of  the  military  stock  film  files 
of  the  War  Department  Central  Film  Library,  also  a  branch  of  the 
Service  Films  Division. 

The  Central  Film  Library  maintains  a  carefully  edited  file  of 
some  ten  thousand  cross-index  cards  describing  the  contents  of 
more  than  two  million  feet  of  training  films,  film  bulletins,  special 
productions,  film  shot  by  the  Signal  Corps  cameramen  in  combat 
areas,  and  miscellaneous  military  footage  procured  for  use  in  official 
War  Department  pictures.  These  stock  shots  are  used  to  expedite 
production,  and  represent  the  most  extensive  collection  of  indexed 
military  subjects,  edited  and  classified  by  specific  types,  available 
for  immediate  use.  For  example,  if  a  piece  of  film  were  received 
by  the  library  showing  ninety-millimeter  anti-aircraft  guns  firing 
at  enemy  planes  in  Tunisia,  it  would  be  indexed  from  a  master  editing 
sheet  ("dope"  sheet,  which  we  make  up  upon  viewing  the  film)  as 
follows : 

1.     North  Africa — Tunisia — Ninety  Millimeter  A  A  gun 
ASF — Ordnance — Ninety  Millimeter  A  A  gun 
AGF — AA  Command — Ninety  Millimeter  AA  gun 
German — Air  force — light  bomber — Junkers  Eighty-eight, 

To  summarize,  the  Service  Films  Division  is  comprised  at  present 
of  branches  that  include  the  Film  Bulletin  Branch,  which  produces 
technical  magazine  reels  of  tests  and  demonstrations;  the  Special 
Productions  Branch,  which  makes  what  the  name  implies;  and  the 
Central  Film  Library. 

Plans  have  been  made  also  for  the  expansion  of  the  Service  Films 
Division  to  include  still  further  developments  in  the  use  of  film  to 
disseminate  information  jointly  with  other  services,  such  as  the 
Navy,  Marines,  and  Coast  Guard.  As  yet,  no  details  can  be  given, 
but  it  will  be  an  important  step  in  the  use  of  film  in  the  War  Effort. 


ANIMATION  IN  TRAINING  FILMS* 
MAJOR  ELLIS  SMITH** 

Animation  is  used  in  military  training  films  when  live-action 
photography  is  impracticable  or  impossible.  Disturbing  or  dis- 
tracting elements  encountered  in  live  action  are  eliminated,  resulting 
in  a  clear,  vivid  portrayal  unhampered  by  non-essential  details. 

Examples  of  the  most  frequent  uses  of  animation  are : 

(1)  Operating  cross-section  views  of  machine  parts,  such  as  the 
internal  workings  of  guns,  the  movement  of  pistons  and  valves  in 
internal  combustion  engines,  the  identification  of  parts,  the  inter- 
relation of  elements,  and  schematic  chemical  or  physical  processes. 

(2)  Tactical  maneuvers  covering  large  areas  of  terrain.     Views 
from  any  altitude  can  be  represented. 

(3)  Visualization  of  intangibles:    gases,  electricity,  magnetism, 
molecular  phenomena,  thermodynamics,  ballistics,  microscopic  ac- 
tivity, can  be  effectively  demonstrated  by  animation. 

(4)  Animated  graphs,  charts,  and  maps  permit  simplified  dynamic 
presentation  of  logistics,  battle  strategy,  and  personnel  functions. 

(5)  Destruction  of  materiel  can  be  shown  by  animation,  thereby 
making  it  unnecessary  to.  destroy  actual  equipment  such  as  tanks, 
barrage  balloons,  buildings,  aircraft,  and  ships. 

(6)  Live-action    photography  often  can  be  clarified  by  super- 
imposing dimension  lines  or  captions,  or  by  a  combination  of  anima- 
tion and  miniature  models. 

(7)  Accurate  miniature  working  models   are  constructed   and 
operated  over  miniature  terrain  in  cases  where  natural  locations 
are   not   available.     This    technique   has   been    successfullly   used 
in  training  films  concerning  large  truck  convoys  and  the  destruction 
of  property  by  incendiary  bombs. 

(Applications  of  the  various  animation  techniques  listed  above  were  illustrated  by 
the  projection  of  a  number  of  scenes  produced  at  the  U.  S.  Army  Signal  Corps  Photo- 
graphic Center.} 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  U.  S.  Army  Signal  Corps  Photographic  Center,  Astoria,  Long  Island,  N.  Y. 

225 


SOUND  RECORDING  AT  THE  SIGNAL  CORPS 
PHOTOGRAPHIC  CENTER* 


MAJOR  GARLAND  C.  MISENER** 

Sound-recording  operations  of  the  Signal  Corps  Photographic 
Center  are  concerned  principally  with  the  production  of  army 
training  films  and  special  service  films.  Sound  is  used  in  training 
films  very  much  the  same  as  in  commercial  teaching  films.  De- 
pending upon  the  type  of  subject  and  its  treatment,  some  pictures 
are  photographed  silent,  then  scored  with  narration  and  essential 
effects;  others  are  taken  in  live  sound  and  augmented  with  effects 
and  library  music  in  the  re-recording  process. 

Narration  and  live  sound  are  cut  into  the  picture  by  editors  in  the 
Editorial  Branch.  The  picture  is  then  turned  over  to  the  Sound 
Branch  for  music  and  effects  editing.  Commercial  effects  records 
are  used  to  a  limited  extent.  In  most  cases,  however,  authentic  sound 
must  be  recorded,  either  wild  or  in  synchronism,  for  in  many  cases 
the  track  is  employed  to  demonstrate  the  characteristic  sounds  of 
weapons,  control  mechanisms,  motor  ailments,  etc.  The  negatives 
of  effects  recorded  specifically  for  a  picture  are  catalogued  in  the 
effects  library  and  stored  for  future  use. 

The  Sound  Branch  embraces  the  following  activities :  field  record- 
ing; recording  of  studio  productions  and  narration  score,  domestic 
and  foreign;  music  and  effects  editing;  re-recording,  domestic 
and  foreign  versions;  installation  and  servicing  of  all  sound-recording 
and  projection  equipment;  practical  instruction  of  combat  unit 
personnel  in  sound  recording. 

The  staff  comprises  both  military  and  civilian  personnel,  including 
many  experienced  studio  and  newsreel  men.  However,  due  to  the 
shortage  of  certain  specialists,  it  has  been  necessary  to  make  replace- 
ments and  additions  to  our  staff  by  selecting  and  training  other  men 
and  women  showing  aptitude  for  sound  production  and  equipment 
maintenance.  The  field  recording  units  usually  comprise  one  officer 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  U.  S.  Army  Signal  Corps  Photographic  Center,  Astoria,  Long  Island,  N.  Y. 

226 


SOUND  RECORDING  227 

and  three  or  four  enlisted  men.  In  the  studio,  the  production  day  is 
divided  into  two  eight-hour  shifts,  in  order  to  realize  the  most  efficient 
use  of  facilities. 

EQUIPMENT 

From  a  single  sound  and  camera  field  unit  of  prewar  days,  the  or- 
ganization has  undergone  a  manifold  expansion,  with  a  commensurate 
broadening  of  studio  and  field  recording  facilities.  Field  recording 
with  portable  channels  was  well  under  way  at  the  time  the  base  of 
operations  was  moved  from  Fort  Monmouth  to  the  Astoria  studios  in 
the  spring  of  1942.  When  the  studios  were  occupied,  two  fixed  chan- 
nels of  the  original  Paramount  Western  Electric  installations  were 
taken  over,  along  with  two  film  machines  and  one  disk  recorder.  In 
addition,  a  new  RCA  re-recording  channel  was  moved  from  Fort 
Monmouth. 

The  portable  recording  equipment  consists  of  a  group  of  RCA 
channels,  purchased  new  and  used  as  available.  The  older  equipment 
includes  two  PM-33  systems,  one  recording  duplex  track  and  the 
other  modified  to  Class  A-B  push-pull  variable  area.1  The  film 
machines  of  the  newer  channels  record  Class  B  push-pull.  The  choice 
of  Class  B  for  original  recording  was  based,  first,  upon  a  desire  to 
eliminate  ground-noise  reduction  equipment,  with  its  heavy  drain 
on  the  B  supply,  its  relatively  complicated  adjustments  and  main- 
tenance, and  the  unfavorable  effects  of  its  exposure  control  upon 
sound  reproduction  due  to  peak-clipping  and  ground-noise  modula- 
tion. Moreover,  the  extended  volume  range  of  Class  B  not  only 
accommodates  more  adequately  original  sound  of  great  volume 
range,  such  as  gunfire  with  its  attendant  breach  and  trajectory 
sounds,  but  it  permits  also  recording  at  lower  modulation  levels 
speech  and  other  sound  in  which  overshooting  produces  objection- 
able distortion.  The  latter  consideration  is  especially  important 
when  the  recording  channel  does  not  include  a  compressor  or  volume 
limiter,  as  is  the  case  with  our  present  portable  equipment. 

One  of  the  Class  B  channels,  less  the  remote  pick-up  equipment, 
is  shown  in  Fig.  1.  The  voltage  and  power  amplifiers  are  mounted 
on  an  iron  framework  in  a  Fiberbilt  case,  with  the  carrying  handles 
attached  to  the  metal  frame.  Cable  connections  to  this  case,  as 
well  as  to  all  other  components  of  the  channel,  are  made  through 
Cannon  P-type,  six-pin  connectors.  Other  fiber  cases  mount  the 
recorder  and  carry  the  magazines,  B  batteries,  and  accessories.  To 


228  MAJ.  G.  C.  MISENER  [j.  s.  M.  P.  E. 

provide  easier  riding  and  to  reduce  vibration,  Lord  mountings  have 
recently  been  installed  on  the  recorder  and  amplifier  cases.  The 
recorder  doors  are  being  modified  to  incorporate  red  glass  viewing 
windows,  in  order  that  the  recordist  may  check  by  observation  the 
film  motion  during  takes. 

Small,  two-position  mixers,  which  can  be  placed  in  any  convenient 
location,  are  used  in  the  field.  The  mixer  panel  includes  a  high-speed 
meter  volume-indicator,  a  head-phone  jack  for  the  MI -3456  high- 


FIG.  1.     Portable  recording  channel,  with  converter  control  panel. 

fidelity  head-set,  a  pair  of  dial  lights  and  a  preamplifier  heater  supply 
voltmeter  and  control.  The  volume  indicator  line  is  strapped  to 
the  recording  bus,  and  the  monitoring  head-set  is  fed  through  a  trans- 
former bridging  the  "VI"  line.  The  recordist  monitors  the  same 
bus  with  crystal  head-phones  which  plug  into  the  recorder  base.  For 
intercommunication  between  the  mixer  and  recordist,  Signal  Corps 
common  battery  field  telephones  are  employed.  The  channel  set-up 
is  indicated  in  Fig.  2.  Western  Electric  618-A  and  630-A  micro- 
phones, the  latter  with  baffles,  are  used  in  the  field,  while  RCA  MI- 
3043-A  unidirectional  microphones  are  generally  used  on  studio  pro- 


Sept.,  1943] 


SOUND  RECORDING 


229 


ductions.  Because  of  its  light  weight,  the  630-A  is  chosen  for  field 
work  with  duralumin  fishpole  booms.  The  feedback  circuit  of  the 
microphone  amplifier  is  adjusted  for  normal  high-frequency  film-loss 
equalization.  The  mixer  circuit  consists  of  two  250-ohm  Daven 
volume  controls  paralleled  through  a  fixed  matching  pad. 

The  main  amplifier  case  mounts  an  MI -102 13  voltage  amplifier, 
a  low-pass  filter,  and  an  MI-3233-C  bridging  power  amplifier.  Ad- 
justable dialog  equalization  has  been  provided  in  the  form  of  variable 
resistance  in  parallel  with  an  added  interstage  coupling  capacitor 
in  the  power  amplifier.  A  series  of  fixed  resistors  on  the  various 
positions  of  a  rotary  gang  switch  comprise  the  variable  resistance, 
with  the  switch  limited  to  screwdriver  operation.  The  low-pass 
filter  consists  of  a  constant-^  section  and  a  shunt  w-derived  section 
in  cascade,  shunt- terminated  and  unbalanced,  using  air-core  coils 


MICROPHONE 

MIXER          LL         ) 

VOLTAGE 

LOW  PASS 

^Snin 

RECC 

ROER 

AMPLIFIER 
MI-10209 

^  -M 

AMPLIFIER 
MI-I02I3 

FILTER 
7000  CW 

AMPLIFIER       ] 
M.-3233B        |           | 

CL( 

3301 

* 

Ir 

r-  i£J      L 

I2AWOV 

1 

I 

1 

MI-10209 

•    VOLT 

l«0  AH 
BATTERY 

J 
"I 

6    VOLT 
BATTERY 

1 
I 

160  VOLTS   U 
BATTERIES  | 

i 

| 

12V 

FIG.  2.     Block  schematic  of  portable  channel. 

wound  in  the  sound  shop.  The  case  and  transmission  grounds  are 
isolated  up  to  the  input  of  the  power  amplifier.  This  ground  system, 
plus  the  radio  frequency  choke  in  the  cathode  circuit  of  the  first 
stage  of  the  preamplifier,  minimizes  radio  and  radar  pick-up. 

Plate  and  heater  supply  is  brought  to  the  main  amplifier  case 
through  a  single  six-conductor  cable,  and  is  distributed  to  the  pre- 
amplifiers through  the  low-level  cable  to  the  mixer.  The  portable 
channels  operate  on  a  standard  cable-connection  and  impedance- 
matching  arrangement  which  permits  corresponding  components, 
including  recorders,  to  be  readily  interchanged.  While  the  channels 
are  ordinarily  kept  intact,  this  interchangeability  is  of  prime  im- 
portance in  coping  with  emergencies  and  special  situations. 

The  recorder  is  a  PR-22  type,  with  ultraviolet  optical  system,  and 
is  provided  with  interchangeable  earner  a- type  motors.  The  220- 
volt  synchronous  motor  is  used  on  studio  productions  and  in  the 
field  with  battery-driven  converters.  Some  units  in  the  field  use 
the  d-c — a-c  interlock  system.  The  interlock  motors  are  supplied 


230  MAJ.  G.  C.  MISENER  [j.  s.  M.  P.  E. 

by  a  120- volt  bank  of  airplane  batteries  through  a  control  panel  at 
the  recordist's  position.  The  control  panel  mounts  three  motor- 
cable  receptacles,  individual  field  controls  for  each  motor  and  a  48- 
cps  Frahm  frequency  meter  connected  to  the  rotor  circuit  for  monitor- 
ing the  motor  speed.  The  individual  field  controls  permit  com- 
pensation for  differing  motor  loads,  thus  reducing  any  tendency  to 
hunt. 

Field  units  carry  tungar  battery  chargers,  and  ordinarily  have 
access  to  110- volt  a-c  supply  for  charging  batteries  overnight.  How- 
ever, when  companies  work  on  locations  remote  from  a-c  supply,  a 
standard  Signal  Corps  gasoline-powered  motor-generator  set  is 
carried  for  battery  charging.  The  common  6- volt,  160-ampere-hour 
automotive  type  storage  battery  is  being  standardized  for  low- voltage 
supply.  A  Signal  Corps  extra-heavy-duty  B  Battery  is  employed  for 
B  supply  in  the  field.  For  use  with  the  portable  channels  in  the 
studio,  regulated  B  supplies  have  been  constructed,  employing  stand- 
ard cable  connectors. 

When  using  a  portable  channel  on  studio  production,  the  recorder 
and  main  amplifier  case  are  either  set  up  on  a  double-deck  dolly  in  a 
room  just  off  the  stage,  or  placed  upon  a  bench  in  one  of  the  base- 
ment film-machine  rooms.  For  the  latter  arrangement,  wall  re- 
ceptacles are  provided  for  operating  over  the  permanent  CTA  lines 
to  the  stages,  and  for  d-c  supply  from  rectifiers.  Also  available  for 
studio  use  is  one  RCA  MI-3130-A  mobile  stage  console  or  "tea 
wagon,"  with  a  four-position  mixer  and  adjustable  dialog  equaliza- 
tion. 

The  azimuth  adjustments  of  the  push-pull  recorders,  as  well  as  the 
sensitometric  conditions,  are  checked  as  regularly  as  possible  by 
recording  cross-over2  and  cross-modulation  tests.  Sound  editing 
of  the  push-pull  track  is  accomplished  with  the  aid  of  moviolas 
modified  for  push-pull  pick-up.  This  modification  involves  the 
mounting  of  a  beam-splitter  such  as  that  used  at  Republic  Studios. 
It  consists  simply  of  two  small  prisms  mounted  side  by  side  im- 
mediately below  the  sound-track  scanning  point,  deflecting  the  light 
transmitted  by  the  two  halves  of  the  track  directly  onto  the  cathodes 
of  a  type  920  photocell.  Azimuth  adjusting  screws  have  been  added 
to  the  slit  assembly  to  facilitate  making  the  initial  setting.  The 
adjusting  screws  may  be  removed  after  the  setting  has  been  tied  off 
with  the  clamping  screws. 

One  Western  Electric  studio  channel  is  used  almost  exclusively 


Sept.,  1943] 


SOUND  RECORDING 


231 


for  narration  scoring,  domestic  and  foreign,  while  the  second  is  used 
on  stage  productions  and  scoring.  The  light-valves  are  biplanar, 
clamped-bridge  type,  worked  with  0.5  mil  ribbon  spacing  and  white- 
light  recording.  The  noise-reduction  units  have  been  modified  for 
high-speed  operation.  Mobile  stage  consoles,  built  by  Audio  Pro- 
ductions, are  used  with  the  WE  channels.3  These  consoles  include 
an  adjustable  dialog  equalizer  and  an  RA-150  mixer  amplifier. 
Through  CTA  lines,  the  RA-150  feeds  the  bridging  bus  at  the  main 


FIG.  3. 


Variable-density  film  machine  with  associated  control  panels 
and  intercommunication  devices. 


amplifier  rack.  D -86 840  bridging  amplifiers  drive  the  valve  and  the 
203-B  volume  indicator,  and  supply  the  monitoring  system  with  direct 
bridging  bus  monitor.  Photoelectric-cell  monitoring  also  is  pro- 
vided, with  both  monitors  fed  selectively  into  a  B-42-A  power 
amplifier  which,  in  turn,  feeds  a  200- A  horn  distribution  panel. 
Each  position  on  the  200-A  panel  appears  on  a  monitor-horn  patch 
bay. 

A  Lansing  Iconic  two-way  speaker  system  is  employed  in  the 
monitoring  room  off  the  scoring  stage,  and  10-inch  dynamic  monitor- 
ing speakers  are  mounted  on  baffles  at  the  film  machine  positions. 
Changing  from  direct  to  photoelectric-cell  monitor  is  effected  by 


232 


MAJ.  G.  C.  MISENER 


U.  S.  M.  P.  E 


merely  throwing  a  switch  at  the  mixing  console.  The  recordist  is 
able  to  alternate  between  direct  and  PEC  monitor  at  the  film  machine 
monitoring  speaker,  independently,  by  a  simple  change  in  patching 
on  a  rack  near  the  machine.  One  of  the  recorder  positions  is  shown 
in  Fig.  3. 

Intermodulation  tests4  are  recorded  occasionally  as  a  guide  for 
determining  and  maintaining  optimal  sensitometric  conditions,  and 
the  results  are  checked  with  listening  tests  on  voice  takes. 

Foreign-version  lip  synchronous  scoring  is  accomplished  with  the 
projection  of  loops  of  composite  domestic  prints  for  cuing.  Port- 


FIG.  4.     Block  schematic  of  No.  1  recording  channel. 

able  loop  stands  accommodating  any  loop  up  to  80  feet  are  used. 
With  the  two  projectors  provided  with  loop  stands,  direct  change- 
overs  may  be  made,  which  makes  it  possible  for  the  recording  schedule 
to  proceed  without  delays  for  threading.  A  third  stand  is  available 
for  use  on  loops  exceeding  80  feet  in  length. 

The  Western  Electric  machines  and  associated  cameras,  as  well  as 
the  machines  of  the  re-recording  channel,  are  operated  from  Western 
Electric  interlock  distributors,  of  which  there  are  four.  These 
distributors  are  powered  by  d-c  drivers  which  are  regulated  by 
700-A  control  panels.  The  four  WE  distributors,  plus  two  smaller 
RCA  distributors  with  synchronous  drivers,  appear  on  a  central 
motor  patch  panel.  The  remote  starting  positions  also  appear  on 
this  panel  permitting  the  control  of  any  distributor  to  be  patched  to 


Sept.,  1943] 


SOUND  RECORDING 


233 


FIG.  5(o).     MI-9066-A  re-recorders. 


FIG.  5(&).     Modified  MI-9003-A  Fantasound  re-recorders. 


234  MAJ.  G.  C.  MISENER  [j.  s.  M.  P.  E. 

any  film  machine,  projection,  or  camera  position.  The  RCA  relay 
control  boxes  were  modified  by  the  addition  of  two  relays,  so  that  they 
also  operate  from  the  WE  remote  control  positions,  making  all  six 
distributors  fully  interchangeable  in  their  application. 

Mole  Richardson  type  103-B  microphone  booms  and  per- 
ambulators are  used  on  stage  productions.  Rubber  suspension 
hangers  are  provided  for  all  types  of  microphones,  and  tinsel  adapter 
jumpers  are  used  between  the  microphone  and  the  cloth-covered 


FIG.  6.     Re-recording  monitor  room 

boom  cable.3  Adapters  have  been  made  to  accommodate  the  630 
microphone  in  the  hanger  for  the  618;  this  permits  the  use  of  either 
microphone  with  a  spherical  windscreen  which  fits  into  the  618 
hanger.  The  booms  are  equipped  also  with  gunning  devices. 

The  re-recording  channel  layout  is  shown  in  Fig.  4.  The  four 
MI-9066-A  re-recorders  are  theater- type  heads,  while  the  other  four 
re-recorders  are  modified  Fantasound  heads,  fitted  with  standard 
sound-head  optical  barrels,  and  using  one  of  the  four  Fantasound 
push-pull  beam-splitter  assemblies.5  The  eight  re-recorders  shown 
in  Figs.  5  (a)  and  5(6),  as  well  as  the  main  amplifier  racks  and  the 
PR-23  recorder,  are  installed  in  a  basement  room.  The  re-recorders 


Sept.,  1943]  SOUND  RECORDING  235 

feed  two-stage  PEC  amplifiers,  which  are  essentially  modified  port- 
able microphone  amplifiers,  over  250-ohm  lines.  These  amplifiers 
have  approximately  45-db  gain,  as  well  as  film-loss  equalization; 
they  are  mounted  interchangeably  in  slides  on  platforms  at  the  rear 
of  one  of  the  equipment  racks.  To  facilitate  cross-patching,  the 
sound-head  outputs,  as  well  as  the  PEC  amplifier  inputs  and  out- 
puts and  the  trunks  to  the  re-recording  console,  all  appear  on  a 
patch  bay. 

The  re-recording  console  and  auxiliary  film  editors'  tables  were 
styled  by  Mr.  R.  Holley  of  RCA  to  meet  certain  requirements  of 
this  installation.  The  re-recording  console,  in  relation  to  its  position 
in  the  monitoring  theater,  is  shown  in  Fig.  6.  The  face  of  the  con- 
trol board  is  illuminated  by  a  rectangular  spot  projected  from  a  spot 
mounted  on  the  ceiling.  At  the  base  of  the  screen  is  a  cabinet  con- 
taining a  model  301  volume-indicator  and  a  footage  counter,  both 
of  which  are  imaged  on  a  translucent  screen  by  rear  projection.  The 
counter  is  relay-operated,  with  switching  accomplished  by  a  com- 
mutator attached  to  the  dubbing  projector.  A  switch  on  the  console 
operates  the  footage  counter  reset  solenoid. 

Fig.  7  (a)  shows  the  equipment  layout  on  the  mixing  board  of  the 
console.  There  are  two  4-position  MI-3108-A  re-recording  mixers 
with  a  re-recorder  trunk  normaled  to  each  input  transformer.  Nor- 
maled  between  the  input  transformers  and  the  control  pads  of  the  No. 
1  or  left-hand  mixer  are  MI-10101  re-recording  compensators  and 
type  85- Bl  one-stage  booster  amplifiers.  These  compensation  units 
may  be  patched  into  any  position  of  the  No.  2  mixer  as  well.  The 
output  of  each  mixer  is  amplified  with  a  type  85-B1  booster  amplifier, 
and  the  booster  outputs  are  combined  in  a  mixing  transformer  which 
feeds  the  return  trunk  to  the  main  amplifier  rack.  Appearing  on  the 
console  patch  bay  is  a  compression  section  input  and  output;  this 
section  includes  an  80-cps  high-pass  filter  and  an  MI-10206-A  com- 
pression amplifier  mounted  on  the  main  amplifier  racks,  as  well  as 
a  ceiling  control  at  the  console.  This  section  is  operated  as  a  zero- 
gain  device,  and  may  be  patched  into  the  output  of  either  4- 
position  mixer.  Thus,  the  mixer  is  provided  with  considerable 
flexibility  in  the  selective  use  of  compression  and  compensation  on  the 
various  tracks  handled. 

An  MI-3118-A  utility  attenuator  panel,  a  UTC  Model  4-B  effects 
filter,  and  two  double-pole  double-throw  utility  keys  are  mounted 
on  the  mixing  board  and  appear  on  the  patch  bay.  The  volume- 


236 


MAJ.  G.  C.  MISENER 


[J.  S.  M.  P.  E. 


FIG.  7(a).     Re-recording  console  mixing  panels. 


FIG.  7(6).     Re-recording  console  patch  bay. 


Sept.,  1943]  SOUND  RECORDING  237 

indicator  range  switch,  a  talk-back  intercommunication  set,  a  signal- 
light  switch,  and  a  monitor  volume-control  also  are  mounted  on  the 
center  panel  of  the  console.  At  the  top  of  the  console,  under  the 
hood,  is  an  MI-3176  neon  volume  indicator,6  which  may  be  used  at 
the  mixer's  discretion. 

In  order  to  make  the  patch  bay  readily  available  to  the  mixer,  and 
at  the  same  time  keep  it  out  of  sight  and  protected  from  dirt,  it  is 
recessed  under  a  door  at  the  top  right  side,  as  shown  in  Fig.  7(b). 
Illumination  for  patching  is  automatically  switched  on  when  the 
patch  bay  door  is  opened.  The  jack  strips  are  mounted  on  a  metal 
door  which  swings  up  on  a  hinge,  affording  convenient  access  to  the 
jacks  for  servicing.  All  the  85-B1  amplifiers  are  mounted  on  a  hinged 
rack  inside  the  console  in  such  manner  as  to  afford  convenient  access 
to  the  terminal  strips  and  tubes.  An  intradepartmental  PAX  tele- 
phone set  and  a  telephone  company  set  also  are  installed  in  con- 
venient locations  on  the  console. 

The  console  output  trunk  is  normaled  to  an  Ml-10213  voltage 
amplifier  on  the  main  amplifier  rack.  This  voltage  amplifier  is  to 
be  replaced  by  a  second  compression  amplifier  for  volume  limiting. 
Following  the  gain  amplifier  are  a  45-cps  high-pass  filter  and  an  MI- 
3121-C  adjustable  low-pass  filter  feeding  the  500-ohm  bridging  bus. 
An  MI-3233-B  bridging  amplifier  drives  the  galvanometer,  while  an 
MI-3218-E  ground-noise  reduction  amplifier,  with  logarithmic  char- 
acteristic, actuates  the  ground-noise  reduction  shutters.  An  MI- 
3 110- A  monitoring  decompensator  also  bridges  the  bus  and  feeds, 
through  a  monitor  volume  control  on  the  console,  the  Western  Electric 
sound  system  in  the  re-recording  monitoring  room.  By  turning  a 
switch  in  the  projection  booth,  the  two  TA-7400  projector  sound- 
heads  appear  on  the  patch  bay  of  the  console,  which  permits  dubbing 
sound  from  composite  prints. 

A  second  re-recording  channel  is  being  installed  in  order  to  cope 
with  the  heavy  production  schedule. 

Single-system  sound  cameras  are  used  on  newsreel  type  of  coverage 
for  special  service  films.  The  equipment  consists  of  Wall  cameras 
and  RCA  PM-43  sound  systems,  recording  Class  B  push-pull  with 
ultraviolet  exposure.  A  small  24-volt  storage-battery  unit  provides 
the  A  supply  and  camera  motor  power.  One  man  can  carry  the 
battery,  amplifier,  and  accessory  cases. 

Greatly  appreciated  is  the  splendid  cooperation  given  this  or- 
ganization by  the  equipment  manufacturers  in  the  installation  and 


238  MAJ.  G.  C.  MISENER 

servicing  of  the  sound  equipment.     The  excellent  work  of  the  military 
and  civilian  personnel  of  the  South  Branch  is  also  cited. 

REFERENCES 

1  CARTWRIGHT,  C.  H.,  AND  THOMPSON,  W.  S.:  'The  Class  A-B  Push-Pull 
Recording  System,"  /.  Soc,  Mot.' Pict.  Eng.,  XXXIII  (Sept.,  1939),  p.  289. 

BLOOMBERG,  D.  J.,  AND  LooTENS,  C.  L. :  "Class  B  Push-Pull  Recording  for 
Original  Negatives,"  J.  Soc.  Mot.  Pict.  Eng.,  XXXIII  (Sept.,  1939),  p.  664. 

*  STROCK,  R.  O.:   "Some  Practical  Accessories  for  Motion  Picture  Recording," 
/.  Soc.  Mot.  Pict.  Eng.t  XXXII  (Feb.,  1939),  p.  188. 

*  FRAYNE,  J.  G.,  AND  SCOVILLE,  R.  R. :    "Analysis  and  Measurement  of  Dis- 
tortion in  Variable-Density  Recording,"  /.  Soc.  Mot.  Pict.  Eng.,  XXXII  (June, 
1939),  p.  648. 

6  GARITY,  WM.  E.,  AND  HAWKINS,  J.  N.  A.:  "Fantasound,"  /.  Soc.  Mot.  Pict. 
Eng.,  XXXVII  (Aug.,  1941),  p.  127. 

6  READ,  S.,  JR.:  "A  Neon  Type  Volume  Indicator,"  /.  Soc.  Mot.  Pict.  Eng.t 
XXXVHI  (June,  1937),  p.  633. 


FIELD  CAMERA  PROBLEMS* 
CAPT.  R.  L.  RAMSEY 

At  the  outset  of  the  war  our  photographic  facilities  and  equipment 
were  called  upon  to  fulfill  the  requirements  of  an  all-out  effort.  It 
was  necessary  to  get  good  effective  training  films  into  the  training 
camps  as  soon  as  possible  and  it  has  only  been  through  the  steady 
and  untiring  efforts  of  all  concerned  that  we  have,  in  a  relatively  short 
time,  been  able  to  build  up  staff  and  equipment  into  a  large  working 
unit  capable  of  turning  out  training  films  in  quantity  and  of 
high  quality.  During  the  past  year  many  problems  have  been  en- 
countered and  investigated  relative  to  the  use  of  camera  equipment 
for  photographic  training  pictures. 

While  there  is  considerable  research  and  preliminary  work  and 
thought  required  before  a  training  film  can  be  started,  it  is  difficult 
to  anticipate  every  demand  that  will  be  made  upon  the  cameramen 
in  the  field.  Many  times  it  is  necessary  for  cameramen  to  use  their 
ingenuity  in  the  field  to  obtain  and  record  the  desired  scene  action. 
It  is  not  always  easy,  as  the  resources  that  are  made  available  to  regu- 
lar studio  workers  are  not  at  hand. 

In  many  instances  the  type  of  work  being  shot  is  of  such  nature 
that  it  must  be  taken  on  a  catch-as-catch-can  basis,  similar  to  news- 
reel  work.  Another  important  consideration  that  confronts  photog- 
raphers of  training  films  is,  "Does  it  Teach ?"  Unlike  regular  photog- 
raphy it  is  sometimes  necessary  to  sacrifice  pictorial  quality  for  the 
purpose  of  emphasizing  a  training  point.  It  is,  however,  necessary 
that  the  picture  composition  at  all  times  be  both  pleasing  and  natural, 
while  at  the  same  time  it  is  instructional.  In  this  connection  it  has 
been  necessary  for  many  experienced  cameramen  coming  into  the 
Signal  Corps  Photographic  Center  to  adopt  new  and  revised  methods 
of  photographing  scenes  and  to  find  ways  of  overcoming  the  obstacles 
that  present  themselves  in  the  field. 

As  an  example  of  such  difficulties,  Fig.  1  shows  the  conventional 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y, 
**  U.  S.  Signal  Corps  Photographic  Center,  Astoria,  Long  Island,  N.  Y. 

239 


240 


CAPT.  R.  L.  RAMSEY 


[J.  S.  M.  P.  E. 


FIG.  1.     Outdoor  overhead  parallel  platform. 


FIG.  2.     Close-up  of  Fig.  1. 


Sept.,  1943]  FIELD  CAMERA  PROBLEMS 


241 


FIG.  3.     A  crude  but  practicable  impromptu  boom. 


FIG.  4.     Shooting  under  difficulties. 


242 


CAPT.  R.  L.  RAMSEY 


[J.  S.  M.  P.  E. 


type  of  overhead  parallel  platform  used  in  filming  one  of  our  recent 
training  films.  While  this  equipment  is  similar  to  what  would  be 
used  in  a  regular  commercial  studio  it  shows  that  shooting  training 
films  in  the  field  is  not  a  one-man  job.  Many  times  it  is  necessary 
to  have  two  or  three  cameras  working  on  the  same  shot.  Fig.  2 
is  a  close-up  of  the  same  parallel  assembly,  showing  the  kind  of  set- 
up and  camera  equipment  used.  As  can  be  seen,  this  is  regular 
studio  equipment. 


FIG.  5.     Shooting  from  a  fox-hole. 


Fig.  3  illustrates  the  ingenuity  of  some  of  the  men.  It  was  neces- 
sary to  make  a  boom  shot  out  in  the  field,  and  this  crude  but  practical 
boom  was  constructed  out  of  the  available  materials.  While  it  was 
indeed  crude,  it  did  the  job,  which  was  the  all-important  thing  since 
the  work  we  do  is  measured  against  the  time  consumed. 

Fig.  4  shows  another  kind  of  shot  we  are  sometimes  called  upon  to 
make.  It  illustrates  a  rather  cramped  shooting  position  for  full-size 
camera  equipment.  In  most  instances  there  is  not  sufficient  time 
or  facilities  for  doing  such  photography  inside  the  sudio,  where 
special  lighting  and  equipment  can  be  used.  Here  again,  the  camera- 


Sept.,  1943] 


FIELD  CAMERA  PROBLEMS 


243 


man  must  use  his  ingenuity  and  take  advantage  of  the  available  equip- 
ment to  obtain  the  desired  effect. 

Fig.  5  shows  an  Eyemo  Camera  being  used  in  a  fox-hole  with  army 
trucks  running  overhead,  and  illustrates  again  the  variety  of  equip- 


FIG.  6.     Trailer  and  jeep. 

ment  necessary  for  filming  training  pictures.  It  is  often  necessary 
to  assemble  equipment  for  short-order  jobs,  and  locations  for  shooting 
are  usually  in  remote  parts  of  the  country.  For  such  assignments 
it  is  necessary  to  supply  the  crew  with  equipment  suitable  for  any 


FIG.  7.     The  contents  of  the  trailer. 


sort  of  photography  they  may  encounter.  With  the  benefit  of  past 
experience  and  a  knowledge  of  the  various  difficulties  encountered, 
we  set  forth  to  assemble  an  experimental  mobile  camera  unit.  The 
considerations  confronting  us  are  that  the  assembly  of  equip- 


244 


CAPT.  R.  L.  RAMSEY 


[J.  S.  M.  p.  E 


FIG.  8.     Cameras  in  position. 


FIG.  9.     Mounting  of  the  Mitchell,  and  the  hydraulic  pedestal. 


Sept.,  1943]  FIELD  CAMERA  PROBLEMS  245 

ment  should  be  compact,  light  in  weight,  readily  mobile,  and  suit- 
able for  all  kinds  of  photography. 

Fig.  6  shows  the  trailer  attached  to  the  jeep  which  is  used  for  con- 
veying the  entire  outfit.  We  are  all  aware  of  the  versatility  of  the 
jeep,  and  in  designing  the  trailer  we  endeavored  to  make  it  just  as 
practical.  The  trailer  is  equipped  with  electric  hydraulic  brakes 
and  is  completely  protected  against  weather.  It  measures  ap- 
proximately 5  X  6  X  6  ft,  and  weighs  2700  pounds  whem  com- 
pletely loaded. 

Fig.  7  shows  the  contents  of  the  trailer.  A  standard  Mitchell 
camera  is  provided  which  can  be  mounted  on  a  hydraulic  pedestal, 
which  is  a  permanent  part  of  the  jeep.  The  camera  can  be  raised 
or  lowered  as  necessary,  and  the  usual  gyro  head  serves  all  the  pur- 
poses of  a  rigid  mounting  for  stationary  and  mobile  work.  Tripods 
of  various  sizes  are  also  provided  for  mounting  the  camera  when  it 
is  to  be  used  in  the  field.  A  400-ft  spider  Eyemo  is  available,  as 
is  also  a  100-ft  model  when  it  is  necessary  that  hand-held  shots  be 
made.  A  4  X  5  Speed  Graphic  still  camera  and  complete  accessories 
are  also  provided.  Two  broad-light  units  and  one  spotlight  are 
included.  The  lighting  equipment  can  be  operated  on  regular  electric 
supply  lines,  when  available.  A  field-developing  kit,  reflectors, 
additional  magazines,  and  all  the  other  expendables  required  are  also 
included. 

Fig.  8  shows  the  outfit  with  two  cameras  mounted  for  photo- 
graphing. The  top  of  the  trailer  is  flat,  so  we  have  the  equivalent 
of  an  upright  platform. 

Fig.  9  shows  the  mounting  of  the  Mitchell  Camera  and  the  hy- 
draulic pedestal.  This  pedestal  is  an  integral  part  of  the  jeep,  rigidly 
mounted  and  reinforced  for  stationary  or  travelling  shots.  It  is 
raised  or  lowered  by  the  means  of  a  foot-pedal  at  the  base.  An 
extension  to  the  pedestal  is  provided  it  the  camera  needs  to  be  raised 
beyond  the  limits  of  the  hydraulic  lift. 

The  illustrations  may  convey  some  idea  of  the  kind  of  work  being 
done.  The  jeep  and  trailer  combination  is  purely  an  experimental 
assembly,  but  already  many  uses  have  been  found  for  it. 


MULTIPLE-FILM  SCENE  SELECTOR* 
CAPT.  HARRY  W.  LEASIM** 

The  Western  Union  Engineering  Laboratories  have  just  completed 
installation  of  five  multiple-film  scene  selectors  in  The  Pentagon, 
Washington,  D.  C.  These  units  are  used  by  the  Army  Pictorial 
Service  in  conjunction  with  the  editing  of  motion  picture  films. 

Prior  to  the  installation  of  the  mechanism,  it  was  the  custom  to 
show  the  film  to  one  person  at  a  time.  This  person  would  actuate  a 
buzzer  whenever  he  saw  a  portion  of  the  projected  film  he  wished  to 
have  reprinted  for  his  purpose.  The  operator  in  the  projection 
room  inserted  a  piece  of  paper  into  the  take-up  reel,  and  the  process 
was  called  "papering"  the  film.  Many  hours  were  expended  in  this 
individual  viewing  of  the  same  film  as  many  representatives  of  various 
branches  of  the  Army  had  to  see  the  film  to  determine  what  parts, 
if  any,  would  be  reacquired  by  their  respective  organizations. 

The  director  of  Army  Pictorial  Service  assigned  qualified  officers 
to  find  a  solution  of  this  problem.  Knowing  of  several  types  of 
devices  in  satisfactory  use  by  the  Western  Union  Telegraph  Company, 
a  meeting  was  arranged  with  Mr.  Dudley,  Chief  Engineer  of  the 
Western  Union  Company,  and  his  assistant,  Mr.  Dirkes.  The 
problem  was  discussed  with  them  and  several  types  of  equipment 
were  inspected  with  the  point  of  view  that  any  equipment  that  would 
require  designing  and  retooling  in  manufacturing  would  not  be  desir- 
able in  view  of  the  urgency  of  procuring  the  device.  The  Western 
Union  Reperforators  10 A  were  found  to  be  satisfactory  for  the  basic 
purpose. 

Each  perforated  tape  is  capable  of  bearing  five  intelligence  holes 
and  one  feed-hole,  perforated  transversely  to  the  length  of  the  tape 
at  each  tenth  of  an  inch  of  tape.  The  reperforators  are  so  arranged 
that  each  horizontal  row  of  holes  is  associated  with  an  editor  so  that 
on  each  perforated  tape  the  requests  of  five  editors  will  be  recorded. 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  U.  S.  Army  Pictorial  Service,  Washington,  D.  C.;    deceased,  June  24,  1943.. 
while  on  duty  in  California. 
246 


MULTIPLE-FILM  SCENE  SELECTOR 


247 


The  selection  of  film  is  made  by  the  elimination  of  the  associated 
horizontal  row  of  perforated  holes  from  the  tape  when  the  part  of  the 
film  desired  is  being  ordered. 

The  mechanism  is  arranged  so  that  with  the  progression  of  one  foot 
of  film  through  the  projector  one  transverse  row  of  five  holes  will  be 
perforated  in  the  tape. 


FIG.  1.     Lead  table  (left)  and  auxiliary  table  (right). 


The  unit  consists  of  a  so-called  lead  table  and  a  number  of  auxiliary 
tables,  each  of  which  records  the  requests  of  five  editors.  In  the 
installation  recently  made,  one  of  the  sets  consists  of  a  lead  table  and 
three  auxiliary  tables,  permitting  twenty  editors  to  register  their 
requests.  Four  auxiliary  tables  can  be  added,  and  the  number  of 
editors  increased  to  forty. 

Each  editor  is  provided  with  a  switch  and  light  unit  at  his  writing 
desk  position.  As  he  watches  the  picture,  he  makes  a  request  for 


248 


CAPT.  H.  W.  LEASIM 


[J.  S.  M.  P.  E. 


part  of  film  by  rocking  a  Levolier  switch  in  the  unit.  A  red  lamp, 
also  a  part  of  the  unit,  glows,  indicating  that  the  request  is  being 
registered.  When  no  more  film  is  desired,  the  editor  again  rocks 
the  switch  and  the  light  is  put  out,  indicating  that  the  request  is 
ended.  The  mechanism  is  capable  of  registering  requests  for  both 
35  and  16-mm  film. 

The  prepared  tape,  when  ready  for  the  cutting  room,  is  run  through 
a  multiple  film  scene  selector  tape  meter  (Reader).     The  tape  meter 


FIG.  2.     Close-up  of  reperforator  10 A . 


counter  is  set  to  zero,  and  the  tape  is  placed  under  the  latch  at  the 
starting  point.  It  is  speedily  fed  through  a  tape  transmitter  until 
a  request  is  encountered,  whereupon  one  of  a  series  of  lamps  is  lighted, 
indicating  in  which  row  of  holes  a  request  is  recorded  and  stopping 
the  tape  so  that  the  operator  may  note  the  point  in  the  film  at  which 
the  request  was  made.  The  switch  associated  with  the  lamp  is  then 
thrown  and  the  machine  progresses  until  such  time  as  another  re- 
quest is  made  or  the  initial  request  is  ended,  whereupon  another  lamp 
is  lighted  and  another  reading  made. 


Sept.,  1943]  MULTIPLE-FILM  SCENE  SELECTOR 


249 


FIG.  3.      Impulse  unit  3A. 


FIG.  4.     Lead  table  and  three  auxiliary  tables  in  the  Pentagon  Build- 
ing installation. 


250 


CAPT.  H.  W.  LEASIM 


Fig.  1.  shows  a  lead  table  (left)  and  auxiliary  table  (right).  The 
covers  have  been  raised  to  show  the  mechanism.  Fig.  2  is  a  close- 
up  of  Reperforator  10 A  and  Fig.  3,  the  impulse  unit  3A.  Fig.  4 
shows  one  lead  table  and  three  auxiliary  tables  installed  in  the 
auditorium  in  The  Pentagon  Building.  Fig.  5  shows  the  tape 
meter. 


FIG.  5.     Tape  meter. 

The  installation  is  now  operating  very  satisfactorily.  The  mul- 
tiple-film scene  selector  allows  twenty  representatives  to  review 
the  film  at  the  same  time  and  provides  for  them  access  to  the  initial 
showing  and  selection  of  film  so  that  the  interested  Services  will  have 
copies  of  films  they  desire  without  any  loss  of  time. 


FILM  DISTRIBUTION* 

LT.  JAMES  D.  FINN** 

It  is  certainly  calling  attention  to  the  obvious  to  state  that  all  the 
effort  in  planning  and  producing  training  films  would  be  wasted 
without  an  efficient  system  of  distribution  that  would  put  the  films  at 
the  right  places  and  at  the  right  times  for  effective  use.  With  millions 
of  men  in  our  Army  scattered  all  over  the  continental  United  States 
and  in  many  foreign  theaters,  efficient  film  distribution  assumes  the 
proportions  of  a  tremendous  problem  in  administration  and  supply. 

After  months  of  work,  a  new  system  of  decentralized  training 
film  distribution  has  been  worked  out.  It  is  the  purpose  of  this 
paper  to  describe  the  functioning  of  the  distribution  of  all  United 
States  Army  films  under  this  new  decentralized  system. 

Since  training  films,  •  film-strips,  film  bulletins,  and  information 
films  are  not  produced  for  theatrical  entertainment,  they  can  not 
be  distributed  on  the  same  basis  as  theatrical  films.  Army  films 
must  be  available  at  all  times  for  showing  to  the  men  at  any  phase 
in  the  training  period.  The  vital  message  of  the  films — a  message 
that  may  mean  the  difference  between  life  and  death  on  the  battle- 
field— must  not  be  left  to  chance.  Accordingly,  it  has  been  necessary 
to  set  up  libraries  of  films  and  film-strips  at  all  centers  where  troops 
are  in  training.  These  libraries  act  as  the  supply  agencies. 

For  the  administration  and  housekeeping  purposes  of  the  Army, 
there  are  nine  Service  Commands  in  the  United  States.  The  Com- 
manding General  of  each  of  these  Service  Commands  is  responsible 
for  all  housekeeping  and  administration  of  the  posts,  camps,  and 
stations  within  the  several  States  comprising  his  command. 

The  basic  unit  of  the  Army  film  distribution  system  is  the  Central 
Distribution  Library  in  the  Headquarters  of  each  Service  Command. 
These  Central  Libraries  have  two  distinct  functions.  One  function 
is  to  supply  films  on  loan  to  installations  in  the  Service  Command 


*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  U.  S.  Army  Pictorial  Service,  Washington,  D.  C. 


251 


252  LT.  J.  D.  FINN  [j.  s.  M.  p.  E. 

that  are  not  large  enough  to  have  libraries.  These  installations  in- 
clude ROTC  Departments,  Ordnance  bases,  depots,  and  other  small 
and  isolated  establishments.  The  second  function  of  the  Central 
Distribution  Library  is  to  act  as  a  supply  point  for  the  various 
libraries  at  posts  and  camps. 

The  libraries  at  posts,  camps,  and  stations  within  a  Service  Com- 
mand are  called  sub-libraries.  These  libraries  are  divided  into  four 
classes,  based  upon  the  soldier  population  they  serve.  This  classi- 
fication of  libraries  A,  B,  C,  and  D  exists  mainly  to  control  the 
amount  of  projection  and  library  equipment  issued. 

Requests  for  additional  prints  of  films  for  permanent  retention 
are  forwarded  from  the  sub-libraries  to  the  Central  Distribution 
Library,  and  the  orders  are  filled  from  stock.  On  initial  distribution 
of  new  films,  the  Central  Library  makes  recommendations  to  the 
Army  Pictorial  Service,  and  the  prints  are  supplied  direct  in  accord- 
ance with  these  recommendations.  Sub-libraries  may  obtain  prints 
on  loan  from  the  Central  Libraries  at  any  time,  and,  if  the  need  arises, 
they  may  order  prints  for  permanent  retention. 

In  order  to  keep  the  Service  Commands  informed  so  that  initial 
distribution  recommendations  may  be  made*  and  acted  upon  without 
delay,  the  Army  Pictorial  Service  furnishes  information  on  the  scope 
of  the  film  and  on  the  distribution  recommended  by  the  approving 
agencies. 

This  system  has  been  evolved  so  that  the  right  subjects  get  to  the 
right  places  and  little  raw  stock  is  wasted.  The  Service  Command, 
for  example,  knows  that  the  1000th  Cavalry  is  mechanized  and  has 
no  use  for  such  a  title  as  the  Horse  Gas  Mask,  whereas  if  prints  were 
distributed  directly  from  Washington  without  these  recommendations 
it  might  be  possible  that  the  Horse  Gas  Mask  would  end  up  on  the 
shelf  of  a  library  serving  tank  units. 

Some  of  the  libraries  within  a  Service  Command  are  small  and 
specialized  and  do  not  need  to  be  included  in  any  initial  distribution. 
These  libraries  are  called  Auxiliary  Libraries  and  are  serviced  from 
the  Central  Library  or  nearest  sub-library.  Only  occasionally  are 
prints  required  for  permanent  retention  by  these  libraries.  The 
designation  of  auxiliary  libraries  also  prevents  stock  from  being 
wasted  and  films  from  resting  for  months  on  library  shelves. 

The  basic  system  of  film  distribution  for  Army  training  films  then 
revolves  around  the  library  system.  The  nine  Central  Libraries, 
the  sub-libraries,  and  auxiliary  libraries  stemming  from  them  form  a 


Sept.,  1943]  FILM  DISTRIBUTION  253 

distribution  network  that  reaches  out  and  touches  the  training  of 
every  soldier  in  the  Army. 

The  American  soldier,  however,  these  days  is  wandering  far  from 
his  native  shores;  and  wherever  large  concentrations  of  men  go, 
the  film  distribution  system  must  follow  them.  Training  takes 
place  at  overseas  bases,  and  modern  training  requires  films.  Hence, 
a  large  number  of  overseas  libraries  have  been  created  and  are  served 
directly  by  the  Army  Pictorial  Service  upon  recommendation  of  the 
various  Theater  Commanders. 

Another  function  of  the  distribution  program  involves  the  use  of 
films  not  made  by  the  Army.  Films  made  by  the  British  Govern- 
ment, for  example,  are  sometimes  adapted  for  use  as  U.  S.  Army 
training  films  and  are  distributed  as  such,  but  many  others  are  made 
available  to  special  Army  installations  on  loan  from  the  Army 
Pictorial  Service.  Films  made  by  the  United  States  Office  of  Educa- 
tion for  the  training  of  industrial  workers  have  been  converted 
where  applicable  and  are  distributed  as  training  films. 

Films  made  for  the  Special  Service  Division  for  orientation  of  the 
American  soldier,  such  as  the  Why  We  Fight  series,  and  films  made 
for  the  Industrial  Relations  Division  of  the  War  Department  Bureau 
of  Public  Relations  for  factory  worker  morale,  are  also  distributed 
on  a  special  basis.  This  latter  type  of  distribution  is  operated  on  the 
familiar  principles  of  theater  booking. 

Training-film  distribution  to  Army  Air  Forces  installations  is  not 
within  the  jurisdiction  of  the  Army  Pictorial  Service.  The  Air 
Forces  operate  their  own  distribution  system. 

So  far  this  paper  has  described  the  functioning  of  the  general 
organization  for  the  distribution  of  Army  films.  A  great  deal 
of  detail  work  is  involved  which  does  not  appear  in  this  general 
description.  For  example,  it  was  necessary  to  develop  a  booking 
system  for  the  Central  Distribution  Libraries,  and  for  the  various 
sub-libraries,  that  would  make  the  right  film  available  at  the  right 
time  for  the  using  unit,  and  at  the  same  time  give  enough  informa- 
tion to  make  it  possible  to  apply  an  inventory  control. 

This  booking  system  is  a  combination  system  incorporating  the 
best  theatrical  and  non- theatrical  practices,  and  certain  new  devices 
made  necessary  by  the  peculiarities  of  military  organization. 

Inventory  control  has  been  established  in  order  to  prevent  use  of 
unnecessary  raw  stock.  Film  stocks  are  checked  by  the  Service 
Corrmands  and  reports  are  rendered  monthly  to  the  Army  Pictorial 


254  LT.  J.  D.  FINN 

Service.  By  comparing  stocks  against  booking  and  needs,  it  is 
possible  for  the  Service  Commands  to  re-allocate  existing  stocks  and 
cut  down  the  making  of  new  prints. 

TABLE  I 

Eighth  Service  Command — Extract  of  Report  on  Attendance 

December,  January,  February, 

1942  1943  1943 

Total  number  of  bookings  (all  libraries)  13,396  14,886  20,159 

Total  number  of  screenings  19,993  25,819  26,919 

Total  attendance  2,284,997  3,550,853  3,745,465 

Total  number  of  previews  held  136  315  341 

Attendance  at  previews  3,959  6,944  4,507 

The  library  reports  serve  also  as  a  rough  check  on  use,  indicating 
by  the  number  of  showings  and  previews  the  extent  to  which  avail- 
able films  are  being  used.  Table  I  shows  a  tabulation  of  a  portion  of 
the  report  from  the  Eighth  Service  Command  for  a  period  of  three 
months.  It  is  obvious  from  a  study  of  the  total  attendance  figures 
that  film  use  grows  even  over  a  short  period  of  time.  When  we  know 
that  in  the  month  of  February,  1943,  the  attendance  at  film  showings 
in  the  Eighth  Service  Command  alone  was  3,745,465,  and  that  the 
message  delivered  at  those  showings  will  help  toward  success  in 
battle,  then  we  know  that  in  a  new  way  we  are  "Getting  the  Message 
Through." 


FILM  UTILIZATION* 


BOYD  T.  WOLFF** 


The  utilization  of  films  in  the  military  training  of  our  Army  must 
be  considered  in  the  light  of  the  tremendous  job  they  have  to  do. 
Our  films  have  to  teach  an  Army  to  win  a  world ;  our  films  are  for  a 
student  body  of  two  million,  five  million,  seven  million,  and  more 
soldiers;  our  films  are  for  a  military  training  program  in  the  greatest 
educational  job  we  have  ever  undertaken — the  establishment  of  a 
University  of  the  American  Army.  Here  is  visual  education  on  a 
scale  that  staggers  the  imagination  of  the  most  ardent  instructional 
film  enthusiast  of  prewar  days. 

This  job  calls  for  something  different,  something  the  makers  of 
films  have  never  done,  something  the  users  of  films  have  never  seen. 
It  calls  for  a  coordinated  program  of  films  complete  from  production 
to  utilization.  The  training  film  program  of  our  Army  is,  therefore, 
something  new  in  visual  instruction. 

It  is  new  in  size,  with  more  than  1000  titles,  in  250  film  libraries, 
for  7,000,000  men. 

It  is  new  in  scope,  with  25  different  series,  for  every  branch  of  the 
Service  from  Air  Corps  to  Transportation  Corps;  with  four  different 
kinds  of  films  (training  films,  film-strips,  film  bulletins,  and  informa- 
tion films)  for  four  different  needs  (motion,  stop-action,  news,  and 
history) ;  and  films  adapted  from  United  Nations  pictures  and  from 
captured  enemy  pictures. 

Producers,  writers,  directors,  cameramen,  technicians,  actors, 
instructors,  projection  equipment  experts  are  putting  together  their 
various  skills  in  one  unified  set-up.  Four  major  aspects  of  visual 
education — production,  distribution,  utilization,  and  evaluation — are 
bound  together  into  a  single  organization,  the  Army,  to  achieve  a 
common  objective — training  combat  troops  to  be  superior  to  the 

*  Presented  at  the  1943  Spring  Meeting  at  New  York,  N.  Y. 
**  U.  S.  Army  Pictorial  Service,  Washington,  D.  C. 

255 


256  B.  T.  WOLFF  [J.  S.  M.  P.  E. 

enemy.  The  purpose  of  this  paper  is  to  show  how  the  Army  utilizes 
films  in  military  training,  and  what  happens  when  the  way  films  are 
used  is  considered  as  important  as  the  kind  of  films  used.  One  of 
the  chief  characteristics  of  Army  films  is  that  they  are  produced  to 
fit  specific  objectives  and  to  match  definite  plans  prescribing  their 
use  in  training. 

Training  Films  are  officially  described  as  "sound  motion  pictures 
produced  specifically  for  use  as  aids  in  expediting  and  standardizing 
instruction  of  the  Army."  Nearly  all  of  them  are  available  in  both 
16  and  35-mm  size.  "Each  film  follows  the  principles  of  accepted 
teaching  method,  is  designed  for  showing  before  a  particular  audience 
group,  and  conforms  in  all  details  to  approved  War  Department 
doctrine  or  technique." 

Film-Strips  are  "series  of  still  transparencies  portrayed  on  in- 
dividual consecutive  frames  of  a  str/ip  of  35-mm  motion  picture 
film." 

Film  Bulletins  "are  designed  to  inform  military  personnel  of  current 
activities  and  developments  in  the  war  effort.  It  is  desired  that 
training  officers  employ  these  bulletins  as  an  orientation  medium  and 
aids  to  instruction  whenever  possible." 

Information  Films  are  being  produced  as  a  new  series  under  the 
general  title,  Why  We  Fight,  to  furnish  military  personnel  with 
historical  and  general  background  information  on  the  war.  All  these 
films  are  coming  to  reflect  the  global  nature  of  the  war  as  more  and 
more  are  made  from  converted  United  Nations  pictures  and  from 
films  captured  from  the  enemy. 

Since  these  different  types  are  produced  not  merely  for  variety's 
sake,  the  kind  of  job  that  each  can  do  best  must  be  clearly  under- 
stood. Training  films  utilize  to  the  fullest  extent  the  element  of 
movement.  In  dealing  with  any  subject,  the  Army  makes  the  most 
of  showing  possibilities  ranging  from  minute  workings  of  the  smallest 
part  to  general  operations  over  a  large  field.  The  utmost  use  is 
made  of  the  camera's  capacity  to  give  a  bird's-eye  view  or  a  micro- 
scopic close-up.  The  training  film  story  may  race  through  time 
or  sweep  over  space,  but  always  its  prime  purpose  is  showing  people 
and  things,  individuals  and  parts,  plans  and  events,  in  action. 

Film-strips  are  utilized  where  the  element  of  stop-action  is  of 
paramount  importance.  Where  an  arrangement  of  relationship 
needs  longer  study  without  consideration  of  movement,  as  in  learning 
nomenclature,  identification,  construction,  etc.,  these  are  held  in 


Sept.,  1943]  FILM  UTILIZATION  257 

view  on  the  screen  while  the  instructor  comments  as  long  as  may  be 
necessary.  In  this  way  the  speed  of  showing  is  adjusted  to  the 
learning  rate  of  the  class. 

Since  basic  technical  principles  of  visual  training  and  conditions  for 
projection  are  common  to  all  film  aids,  however,  the  term  "training 
films"  is  used  hereafter  to  mean  any  or  all  film  aids  except  where 
specifically  differentiated. 

As  to  content  and  subject  matter,  both  training  films  and  film-strips 
are  for  specific  training  in  military  regulations,  mechanics,  techniques, 
and  tactics  in  accordance  with  approved  military  doctrine.  These 
comprise  four  groups  arranged  according  to  training  plans  to  fit 
successive  stages  and  specialized  aspects  of  the  soldier's  instruction. 

First  the  basics,  required  showing  to  recruits  at  Reception  Centers. 
These  pictures  deal  with  first  things  first,  take  nothing  for  granted, 
leave  no  room  for  guesswork,  introduce  the  new  soldier  to  the  Army. 
How  must  the  enlisted  man  conduct  himself?  What  is  expected  of 
him  ?  He  sees  the  film  Military  Courtesy  and  Customs  of  the  Service. 
What  are  the  rules  and  regulations  that  will  govern  his  life  in  the 
Army?  The  A r tides  of  War  answers  this  question.  What  should  he 
do  if  exposed  to  venereal  disease?  Sex  Hygiene  shows  what  to  do  and 
where  to  do  it.  Such  matters  are  dealt  with  plainly.  The  first 
training  films  soon  dispel  any  previous  notions  the  recruit  may  have 
as  to  the  effectiveness  of  old-wives'  remedies  or  quacks'  nostrum 
in  dealing  with  the  facts  of  life.  Along  with  these  he  gets  a  glimpse 
of  the  fundamentals  of  soldiering,  in  a  group  of  films  that  every 
enlisted  man  must  see:  Identification  of  Aircraft,  Adjustment  and 
Inspection  of  Gas  Masks,  Map  Reading,  Anti- Mechanized  Defense, 
Use  of  Natural  Cover  and  Concealment,  Weapons,  Drill,  First  Aid, 
Safeguarding  Military  Information,  etc. 

Second,  third,  and  fourth  groups  of  training  films  and  film-strips 
are  classed  as  mechanical,  technical,  and  tactical,  respectively.  While 
they  are  not  necessarily  programed  in  that  order,  these  are  the  films 
for  advanced  training  of  specialists.  They  are  concerned  with  the 
structure,  assembly,  and  disassembly  of  our  own  secret  weapons,  and 
the  operation  of  vehicles. 

The  film  bulletins  cover  experiments  with,  or  trials  and  tests  on, 
materiel,  or  methods  that  have  not  been  accepted  as  official  doctrine. 
They  help  the  individual  soldier  see  where  his  special  function  fits 
into  the  vast  Army  organization  as  a  whole. 

The  information  films  are  full-length  features  to  give   a  broad 


258  B.  T.  WOLFF  [J.  S.  M.  P.  E. 

perspective  of  the  war  and  the  world  in  which  it  is  being  fought. 
These  films  are  not  intended  to  train  the  soldier  in  special  techniques 
or  knowledge,  or  to  tell  him  directly  how  to  do  anything  better;  they 
are  intended  to  enlist  his  sympathies  and  full  emotional  strength  for 
fighting.  They  are  to  deepen  and  to  extend  his  understanding  of 
our  cause.  They  are  shaped  primarily  to  get  a  response  from  his 
mind  and  heart  rather  than  from  his  hands  and  body,  to  affect  his 
attitudes  rather  than  aptitudes;  but  in  so  doing,  ultimately  to  make 
him  a  totally  better  fighting  man.  Information  films  produced  so 
far  are  Prelude  to  War,  The  Nazis  Strike,  Divide  and  Conquer,  and 
Battle  of  Britain.  Pictures  planned  to  round  out  the  series  are  The 
Battle  of  Russia,  The  Battle  of  China,  and  America  in  the  War. 

None  of  these  films  is  conceived  as  a  substitute  for  the  other. 
Each  has  the  single  message  it  can  get  across  better  than  any  of  the 
others.  It  may  happen  that  a  training  film,  a  film-strip,  a  film 
bulletin,  and  an  information  film  may  be  on  the  same  subject;  but 
each  represents  a  different  approach,  a  different  emphasis  or  treat- 
ment. For  instance,  on  the  subject  of  tanks,  the  training  films 
Armored  Combat  Vehicles,  Armored  Force  Drill,  Basic  Tank  Driving, 
and  Advanced  Tank  Driving  deal  with  types  of  tanks  and  methods  of 
using  them,  explaining  their  potentialities  and  limitations — long 
shots  and  close-ups  in  logical  instructional  sequence,  with  repetition 
and  summary  of  important  points.  The  film-strips  First  Echelon 
Tank  Maintenance,  Tank  Track  Maintenance  for  the  Light  M3  and  the 
Medium  M3  and  Tank  Inspection  cover  common  nomenclature, 
dimensions,  details  of  construction  and  function,  and  diagrams  of 
procedure,  one  step  at  a  time.  The  film  bulletins  U.  S.  Army  Medium 
Tank  M3,  Tank  Obstacles  and  Army  Tank  Destroyers  demonstrate 
trial  methods  of  stopping  tanks  with  obstacles,  under  severe  test- 
ing conditions.  The  information  film  The  Nazis  Strike  shows  the  kind 
of  enemy  tank  action,  in  Czechoslovakia  and  Poland,  that  our  troops 
must  learn  to  combat.  The  Army  instructor  extracts  the  full  value 
of  each  type  of  film  aid  by  using  it  in  planned  relationship  to  the 
others  and  to  his  whole  lesson.  He  sees  to  it  that  the  manner  in 
which  the  film  treats  the  subject  matches  the  way  in  which  he  in- 
tends to  treat  the  lesson.  He  fits  the  film  to  the  sequence  of  activi- 
ties in  training  plans. 

All  these  films  are  tools  of  instruction.  They  are  source  ma- 
terials for  a  method  of  training,  requiring  their  own  method  of 
specialized  technique.  They  are  vital  weapons  in  the  arsenal  of 


Sept.,  1943]  FILM  UTILIZED  259 

democracy.  As  such  they  demand  just  as  much  skill  and  under- 
standing in  then:  use  as  any  other  material  of  modern,  mechanized 
warfare. 

The  first  job  of  the  Army  instructor  is  to  see  that  his  men  know 
how  to  look  at  films.  He  has  to  begin  by  explaining  the  difference 
between  films  "Produced  by  Military  Authorities  for  Military  Per- 
sonnel for  Military  Objectives,"  and  the  kind  of  movies  most  of  them 
are  used  to  going  to  for  amusement.  He  must  explain  why  films  are 
used  in  training  and  why  there  are  different  kinds  of  training  films. 
The  men  have  to  learn  the  difference  between  really  studying  a  film 
and  merely  watching  it  to  see  "How  it  comes  out,"  for  training  films 
have  to  take.  They  must  stick.  They  can  not  afford  to  be  "filed  or 
forgotten." 

Among  other  things,  the  men  have  to  learn  how  to  observe  a  film 
selectively,  systematically,  and  with  concentration;  how  to  take 
notes;  how  to  ask  significant  questions.  The  instructor  has  to  decide 
from  his  knowledge  both  of  his  subject  and  his  men  how  many 
repeat  showings  are  necessary  and  at  which  stages  of  the  lesson  they 
are  needed.  This  varies  as  films  vary  between  "basic"  and  "highly 
specialized  technical"  training  films.  It  varies  as  men  vary  from 
those  barely  able  to  read  to  those  with  college  training. 

Training  films  are  not  presented  as  a  short-cut  to  learning,  or  as 
necessarily  easier  than  other  methods.  In  no  sense  are  training 
films  frills.  They  are  not  meant  to  glamorize  training.  Our  Army 
has  a  lot  to  learn  in  a  little  time,  and  training  films  teach  more,  in  a 
clearer,  faster  way  than  any  other  means  of  instruction.  As  the 
largest  group  of  potential  learners  in  the  world  this  unique  film  audi- 
ence realizes  it  is  there  to  learn  the  most  serious  lessons  in  the  world. 

To  get  this  lesson  across,  the  procedure  for  the  most  effective 
utilization  of  training  films  corresponds  to  the  general  sequence  of 
steps  outlined  in  the  basic  field  manual  on  military  training  as 
follows : 

The  first  step  is  preparation.  Each  film  must  be  previewed  by  the 
instructor  before  showing.  The  instructor  also  must  arrange  in 
advance  for  booking  the  film  and  for  the  equipment,  projectionist, 
and  classroom.  He  must  study  correlative  training  literature. 

The  second  step  is  explanation.  Before  each  film  showing  the  men 
are  given  a  brief  account  of  what  the  film  is  about  and  what  they  are 
expected  to  learn  from  it.  They  are  informed  that  they  will  be 
quizzed  on  its  contents. 


260  B.  T.  WOLFF  [j.  s.  M.  P.  E. 

The  third  is  demonstration.  This  is  the  showing  of  the  film  itself. 
The  instructor  is  responsible  for  setting  up  good  screening  conditions. 

Before  the  filming  he  makes  sure  that  the  right  film  is  ready,  that 
the  projector  is  set  up  and  in  working  order,  and  that  the  screen  is 
placed  within  the  proper  sight  lines,  without  posts  or  other  obstruc- 
tions in  the  line  of  vision.  He  must  arrange  for  maximum  com- 
fort of  the  audience  and  see  that  the  room  is  ventilated  and  darkened 
to  the  extent  of  existent  facilities;  for  it  must  be  remembered  that 
few  of  the  projection  rooms  were  designed  for  screening  purposes. 

The  fourth  is  application.  As  often  as  possible  the  film  lesson  is 
applied  in  practice.  It  is  recognized  that  vivid  as  a  motion  picture 
may  be,  it  is  one  step  removed  from  reality.  The  men  are  taken 
directly  to  such  areas  of  activity  as  the  drill  field,  the  firing  range,  the 
shop,  the  convoy,  the  patrol,  so  that  they  may  make  the  visualized 
experience  their  own  through  seeing,  hearing,  feeling,  doing.  Other 
visual  aids  such  as  models,  sand  tables,  wall  displays,  still  photo- 
graphs, diagrams,  charts,  maps,  etc.,  related  to  the  same  subject 
are  used  as  supplementary  materials  for  study  by  individuals  and 
small  groups. 

The  fifth  is  discussion.  Here  also  the  men  have  a  chance  to 
participate.  They  ask  and  answer  questions.  In  this  phase  of  the 
instruction  they  show  which  things  they  learn  quickly  and  which 
slowly,  where  their  greatest  difficulties  lie  and  how  the  instructor 
can  help  them  most. 

The  sixth  and  last  step  is  examination.  Following  each  screening 
the  instructor  asks  fifteen  questions  which  he  has  previously  written 
on  the  film.  A  unique  method  has  been  worked  out  to  simplify  the 
administration  of  this  quiz. 

Each  soldier  is  provided  with  a  training  film  quiz  card  in  duplicate. 
The  card  has  two  columns  of  fifteen  tabs  each — one  column  for 
answering  "yes"  and  one  column  for  answering  "no."  As  each  of 
the  fifteen  questions  is  asked,  the  student  punches  out  the  tab  that 
he  thinks  gives  the  correct  answer.  When  the  questioning  is  ended 
he  immediately  hands  to  the  instructor  his  duplicate  card,  with  his 
name  on  it,  and  keeps  the  original  as  a  record  of  his  progress  through- 
out the  course.  The  instructor  then  reviews  the  quiz  announcing 
or  writing  on  the  blackboard  the  correct  answers  so  that  each  man 
will  know  his  score  before  leaving  the  classroom. 

The  sequence  of  these  steps  may  be  varied  to  suit  the  circumstances 
and  it  makes  no  essential  difference  whether  the  whole  procedure  is 


Sept.,  1943]  FILM  UTILIZATION  261 

carried  out  during  a  single  day  or  over  a  longer  period  of  time.  The 
instructor  must  know  what  he  is  going  to  do  all  the  way  through 
his  cycle  of  instruction  before  he  starts  a  course.  He  must  take  into 
account  all  possibilities.  He  must  aim  to  use  the  film  in  such  a  way 
that  without  it  something  would  be  missing,  and  with  it  something 
is  added  that  no  other  medium  of  instruction  can  supply. 

Since  training  plans  and  schedules  provide  a  "place  for  every 
film,"  every  film  must  be  used  in  its  proper  place — that  is,  only  in 
connection  with  definite  training  objectives.  These  objectives  are 
set  by  the  highest  training  echelons  which  set  up  long-range  schedules 
called  Mobilization  Training  Programs  for  their  accomplishment. 
Training  programs  that  actually  bring  together  soldiers,  instructors, 
equipment,  time,  and  place  are  worked  out  by  division,  regiment, 
and  battalion  training  officers.  Since  all  training  films  are  designed 
for  use  in  a  larger  plan,  their  full  utilization  is  realized  only  when 
they  are  related  to  other  coordinated  activities  of  military  training. 

To  expedite  the  use  of  training  films  in  the  field,  the  Film  Distribu- 
tion and  Utilization  Branch  of  the  Army  Pictorial  Service  provides 
the  following  services  and  publications : 

Visual  Aid  Coordinators:  for  each  of  the  nine  Service  Commands 
to  give  overall  assistance  on  the  spot  where  the  films  are  actually  used. 
As  consultants  and  trouble  shooters  they  bring  all  possible  help 
from  the  War  Department  to  assist  in  the  installation  of  new  film 
libraries  and  in  the  most  effective  use  of  films  in  training.  What  they 
find  out  in  the  field  helps  to  bring  about  needed  changes  in  pro- 
cedure. 

Basic  Field  Manual  21-7  gives  a  complete  list  of  titles  and  brief 
notes  on  all  training  films,  film-strips,  and  film  bulletins.  It  is 
published  twice  a  year. 

-  War  Department  Training  Circulars,  with  current  information  on 
Army  Films,  are  printed  monthly. 

The  Film  Distribution  and  Utilziation  News  Letter  is  issued  in 
mimeographed  form  bimonthly  with  general  reports  on  most  recently 
approved  and  distributed  films,  and  new  developments  in  film 
utilization  in  the  Service  Commands  and  in  the  Army  Pictorial 
Service. 

Training  Film  Outlines  for  each  training  film  produced. 

Research  Bulletins  announce  results  of  surveys  on  film  utilization. 

Standarized  Quiz  Answer  Cards. 


262  B.  T.  WOLFF 

In  summary,  it  should  be  remembered  that  training  films,  film- 
strips,  film  bulletins,  and  information  films  are  an  integral  part  of 
the  total  military  training  program.  They  are  not  "extra  added 
attractions"  of  military  training.  The  Army  has  gone  all  out  for 
visual  training  and  it  is  bending  every  effort  to  see  that  the  highest 
degree  of  skill  in  their  use  is  developed.  Films  as  materiel  of  war 
are  one  of  the  most  potent  of  weapons  in  our  arsenal  of  democracy. 

It  is  hoped  that  the  private  industrialist  who  may  be  fearful  that 
the  government  is  taking  over  all  film  stock  may  take  comfort  in  the 
fact  that  the  way  is  being  prepared  for  an  educational  film  industry 
in  peacetime  such  as  never  before  has  been  conceived.  It  is  hoped 
that  the  public,  complaining  perhaps  of  fewer  new  films  at  local 
theaters,  will  remember  that  there  are  more  new  films  being  made  to 
help  train  our  Army  to  save  our  lives. 


FIFTY-FOURTH  SEMI-ANNUAL  TECHNICAL  CONFERENCE 


OF  THE 


SOCIETY  OF  MOTION  PICTURE  ENGINEERS 


HOLLYWOOD-ROOSEVELT  HOTEL,  HOLLYWOOD,  CALIF 
OCTOBER  18-22,  INCLUSIVE 


Officers  and  Committees  in  Charge 

HERBERT  GRIFFIN,  President 

EMERY  HUSE,  Past-President  and  Chairman,  Local  Arrangements 

LOREN  L.  RYDER,  Executive  Vice-P resident 

W.  C.  KUNZMANN,  Convention  Vice-P  resident 

A.  C.  DOWNES,  Editorial  Vice-President 

E.  A.  WILLIFORD,  Secretary 

C.  W.  HANDLEY,  Chairman,  Pacific  Coast  Section 

JULIUS  HABER,  Chairman,  Publicity  Committee 

Papers  Committee 


C.  R.  DAILY,  Chairman 
C.  R.  KEITH,  Vice-Chairman  East  Coast 


F.  W.  BOWDITCH 

G.  A.  CHAMBERS 
F.  L.  EICH 

R.  E.  FARNHAM 
J.  L.  FORREST 


J.  FRANK,  JR. 
J.  G.  FRAYNE 
P.  A.  McGuiRE 
E.  W.  KELLOGG 
G.  E.  MATTHEWS 


H.  W.  MOYSE 

W.  H.  OFFENHAUSER 

V.  C.  SHAUER 

S.  P.  SOLOW 

W.  V.  WOLFE 


Reception  and  Local  Arrangements 


H.  J.  CHANON 
J.  G.  FRAYNE 

A.  M.  GUNDELFINGER 

C.  W.  HANDLEY 
E.  H.  HANSEN 
J.  K.  HILLARD 
E.  M.  HONAN 


C.  W.  HANDLEY 
E.  HUSE 


EMERY  HUSE,  Chairman 
M.  S.  LESHING 
W.  C.  MILLER 

R.  H.  McCULLOUGH 

P.  MOLE 
F.  K.  MORGAN 
H.  W.  MOYSE 
W.  A.  MUELLER 

Registration  and  Information 

W.  C.  KUNZMANN,  Chairman 


G.  F.  RACKETT 

H.  W.  REMERSHIED 

L.  L.  RYDER 

C.  R.  SAWYER 

S.  P.  SOLOW 

J.  R.  WILKINSON 

W.  V.  WOLFE 


R.  G.  LlNDERMAN 

H.  SMITH,  JR. 


263 


264        FIFTY-FOURTH  SEMI- ANNUAL  CONFERENCE        [J.  S.  M.  p.  E. 

Publicity  Committee 

G.  R.  GIROUX,  Chairman 

J.  W.  BOYLE  JULIUS  HABER 

C.  R.  DAILY  C.  R.  KEITH 

G.  GIBSON  E.  C.  RICHARDSON 

Luncheon  and  Dinner-Dance  Committee 

LOREN  L.  RYDER,  Chairman 

A.M.  GUNDELFINGER  P.  MOLE  R.  R.  SCOVILLE 

H.  T.  KALMUS  H.  W.  MOYSE  S.  P.  SOLOW 

E.  M.  HONAN  W.  A.  MUELLER  J.  R.  WILKINSON 

E.  HUSE  H.  W.  REMERSHIED  W.  V.  WOLFE 

Hotel  and  Transportation 

A.  M.  GUNDELFINGER,  Chairman 

A.  C.  BLANEY  A.  F.  EDOUART  O.  F.  NEU 

L.  W.  CHASE  H.  GOLDFORB  G.  E.  SAWYER 

H.  J.  CHANON  G.  T.  LORANCE  N.  L.  SIMMONS 

L.  E.  CLARKE  W.  C.  MARCUS  W.  L.  THAYER 

Projection  Committee 

35-Mm  Programs 
R.  H.  McCuLLOUGH,  Chairman 
L.  R.  ABBOTT  W.  E.  GEBHARDT,  JR.  C.  R.  SAWYER 

B.  FREERICKS  W.  W.  LINDSAY,  JR.  W.  V.  WOLFE 

C.  R.  RUSSELL 
Officers  and  Members  of  I.A.T.S.E.  Locals  150  and  165 

16-Mm  Programs 

H.  W.  REMERSHIED,  Chairman 

A.  H.  BOLT  A.  M.  GUNDELFINGER 

C.  DUNNING  J.  RUNK 

Ladies  Reception  Committee 

MRS.  C.  W.  HANDLEY,  Hostess 

There  will  be  o  special  or  prearranged  ladies  entertainment  program  during 
the  five-day  1943  Fall  Conference.  However,  a  reception  parlor  will  be  available 
in  the  Hotel  where  the  ladies  may  meet  daily.  The  ladies  are  cordially  invited 
to  attend  the  functions  of  the  Conference. 

TENTATIVE  PROGRAM 

Monday,  October  18th 
9: 30  a.m.    Hotel  Lobby;  Registration. 
The  program  for  the  morning  of  this  date  will  be  announced  later. 

12:30  p.m.     Terrace  Room;  Informal  Get-Together  Luncheon  for  members,  their 
guests,  and  families.    The  luncheon  program  will  be  announced  later. 


Sept.,  1943] 


FIFTY-FOURTH  SEMI-ANNUAL  CONFERENCE 


265 


Due  to  the  hotel  labor  and  food  situation,  it  is  imperative  members  procure 
their  luncheon  and  dinner-dance  tickets  at  the  time  of  registering  so  that  the 
Arrangements  Committee  may  provide  the  necessary  accommodations. 

2: 00  p.m.     Blossom  Room;  General  Session. 

8: 00  p.m.     General  Session;  the  location  will  be  announced  later. 

Tuesday,  October  19th 

10:00  a.m.     Hotel  Lobby;  Registration.     Open  morning. 
2: 00p.m.     Blossom  Room;  General  Session. 
8: 00  p.m.     General  Session;  the  location  will  be  announced  later. 

Wednesday,  October  20th 

9:30  a.m.    Hotel  Lobby;  Registration. 
10:00  a.m.     Blossom  Room;  General  Session. 

2 :00  p.m.     Open  afternoon  for  recreational  program  to  be  announced  later. 
8: 00  p.m.     Blossom  Room;   SMPE  Fifty-Fourth  Semi-Annual  Dinner-Dance. 
The  program  for  the  evening  will  be  announced  later.     ( Dancing  until 
12:30  a.m.;   strictly  informal  business  dress  and  uniforms  only.) 

Thursday,  October  21st 

10:00  a.m.     Open  morning. 
2 : 00  p.m.     Blossom  Room;  General  Session. 
8: 00  p.m.     General  Session;  the  location  will  be  announced  later. 

Friday,  October  22nd 

10:00  a.m.  Blossom  Room;  General  Session. 
2: 00  p.m.  Blossom  Room;  General  Session. 
8 : 00  p.m.  Blossom  Room;  General  Session  and  Adjournment. 

Conference  Headquarters 

The  Pacific  Coast  Section  Officers  have  selected  the  Hollywood-Roosevelt 
Hotel,  Hollywood,  Calif.,  as  headquarters  for  the  1943  Fall  Technical  Conference 
with  the  following  per  diem  rates  guaranteed  by  the  hotel  management. 

Room  with  bath,  one  person $3.85 

Room,  double  bed,  with  bath,  two  persons 5.50 

Room,  twin  beds  with  bath,  two  persons 6.60 

Small  suite,  parlor,  bedroom  with  bath,  single  or  double  occupancy 8.80 

Room  reservation  cards  will  be  mailed  to  the  membership  early  in  September, 
and  should  be  returned  immediately  to  the  Hotel.  All  booked  accommodations 
will  be  guaranteed  when  confirmed  by  the  Hotel  Management.  Reservations 
are  subject  to  cancellation  at  any  time  prior  to  the  Conference. 

Indoor  and  outdoor  parking  facilities  will  be  available  at  the  Hotel  head- 
quarters if  desired. 


266  FIFTY-FOURTH  SEMI-ANNUAL  CONFERENCE  [J.  S.  M.  p.  E. 

The  Conference  registration  headquarters  will  be  located  in  the  Hotel  Lobby, 
and  members  and  guests  will  be  expected  to  register  and  receive  their  badges 
and  identification  cards.  The  registration  fees  are  used  to  help  defray  the 
Conference  expenses,  and  cooperation  in  this  respect  will  be  greatly  appreciated 
by  the  Local  Arrangements  Committee. 

The  identification  cards  will  provide  admittance  to  all  sessions  at  and  away 
from  the  Hotel.  They  will  be  honored  also  at  the  following  de  luxe  motion 
picture  theaters  on  Hollywood  Boulevard,  in  the  vicinity  of  the  Hotel:  Fox 
West  Coast  Grauman's  Chinese  and  Egyptian  Theaters,  Hollywood  Paramount, 
Hollywood  Pantages,  and  Warner's  Hollywood  Theater. 

Eastern  and  Mid-western  members  who  are  planning  to  attend  the  1943  Fall 
Conference  should  consult  their  local  railroad  passenger  agent  regarding  train 
schedules,  available  accommodations,  rates,  and  stop-over  privileges  en  route. 
If  a  San  Francisco  stop-over  is  included  in  the  trip  to  the  West  Coast,  the  Con- 
ference Committee  suggests  the  Mark  Hopkins  Hotel  on  "Nob  Hill."  Reserva- 
tions should  be  mailed  to  Mr.  R.  E.  Goldsworthy,  Assistant  Manager  of  the 
Mark  Hopkins. 

Note. — The  1943  Fall  Technical  Conference  is  subject  to  cancellation  if  later 
deemed  advisable  in  the  national  interest. 

W.  C.  KUNZMANN 
Convention  Vice-President 

PAPERS  PROGRAM  OF  THE  FIFTY-FOURTH  SEMI-ANNUAL 
TECHNICAL  CONFERENCE 

The  Papers  Program  for  the  Fifty-Fourth  Semi- Annual  Technical  Conference 
is  progressing  beyond  expectations,  considering  the  difficulties  of  the  times.  Al- 
though the  arrangement  of  the  sessions  and  the  scheduling  of  the  papers  in  the 
sessions  have  not  yet  been  completed,  the  Papers  Committee  is  pleased  to  present 
the  following  list  of  titles  that  will  be  included.  Accompanying  a  number  of  the 
papers  will  be  film  presentations  and  demonstrations.  The  names  of  authors 
omitted  from  the  following  list  will  be  given  in  the  Tentative  and  Final  Programs. 
Some  of  the  presentations  will  be  given  at  the  studios,  and  at  least  one  or  pos- 
sibly two  afternoons  will  be  left  free  for  diversion  or  other  interests. 
"Single  Film  Portable  Recording  Systems" ;  RCA  Victor  Division,  Radio  Corpora- 
tion of  America. 
"Sound  Installations  in  Washington";  RCA  Victor  Division,  Radio  Corporation 

of  America. 
"Accoustical  Research  Facilities  at  the  RCA  Princeton  Laboratories";     Radio 

Corporation  of  America. 
"New  Duplex  Loud  Speaker";    J.  B.  Lansing,  Altec-Lansing  Corp.,  Hollywood, 

Calif. 
"High-Quality  Communication  and  Power  Transformers";    Ercell  B.  Harrison, 

Altec-Lansing  Corp.,  Hollywood,  Calif. 
"250-Watt  Class-B  Audio  Amplifier";    John  W.  Hilliard,  Altec-Lansing  Corp., 

Hollywood,  Calif. 

"Post- War  Television  Planning  and  Requirements";     Klaus  Landsberg,  Tele- 
vision Productions,  Paramount  Studios,  Hollywood,  Calif. 


Sept.,  1943  J     FIFTY-FOURTH  SEMI-ANNUAL  CONFERENCE  267 

"A  Simplified  Variable- Density  Sound  Developer";  Paul  Zoff  and  F.  J.  Twining, 
Columbia  Pictures  Corp.,  Hollywood,  Calif. 

"Walt  Disney  Studio— a  War  Plant";  Carl  Nater,  Walt  Disney  Studios,  Burbank, 
Calif. 

"Present  and  Proposed  Use  of  Plastics  in  the  Motion  Picture  Industry";  Barton 
H.  Thompson,  Paramount  Pictures,  Inc.,  Hollywood,  Calif. 

"Sixteen-Mm  Color  to  35- Mm  Black-and- White" ;  Carroll  H.  Dunning,  Dunning 
Process  Co.,  Hollywood,  Calif. 

"The  Future  of  the  16-Mm  Sound-Film  Industry";  John  A.  Maurer,  J.  A. 
Maurer,  Inc.,  New  York,  N.  Y. 

"What  to  Expect  of  Direct  16-Mm";  Lloyd  Thompson,  The  Calvin  Company, 
Kansas  City,  Mo. 

"Improvements  in  Sound  Recording  Equipment";  L.  F.  Brown,  ERPI  Division 
of  the  Western  Electric  Company,  Hollywood,  Calif. 

"A  New  Sound  Reproducer";  ERPI  Division  of  the  Western  Electric  Company, 
Hollywood,  Calif. 

"A  New  Single-Film  Recording  Camera";  George  Worrall,  Mitchell  Camera 
Company,  Hollywood,  Calif. 

"Duplication  of  Kodachrome  Original,  with  Enlargements,  Reduction,  and  Color 
Correction";  Earl  Morgan  and  Roy  Peck,  Paramount  Pictures,  Inc.,  Holly- 
wood, Calif. 

"Transfer  of  Kodachrome  Emulsion  to  Lantern-Slide  Glass";  Barton  H.  Thomp- 
son, Paramount  Pictures,  Inc.,  Hollywood,  Calif. 

"High-Efficiency  Stereopticon  Projection  for  Color  Background  Shots";  A.  C. 
Zoulis  and  Farciot  Edouart,  Paramount  Pictures,  Inc.,  Hollywood,  Calif. 

"A  200-Mil  Push-Pull  Sound- Recording  System";  L.  D.  Grignon  and  J.  P.  Cor- 
coran, Twentieth  Century-Fox  Film  Corp.,  Hollywood,  Calif. 

"A  Visual  Light- Valve  Checking  Device";  J.  P.  Corcoran,  Twentieth  Century- 
Fox  Film  Corp.,  Hollywood,  Calif. 

"Improvements  in  the  Disney  Scoring  Stage";  C.  O.  Slyfield,  Walt  Disney  Pro- 
ductions, Burbank,  Calif. 

"Improvements  in  the  Columbia  Scoring  Stage";  J.  Livadary,  Columbia  Pic- 
tures Corp.,  Hollywood,  Calif. 

"New  Scoring  Stage,  Shell,  and  Vocal  Booth  Design";  Loren  L.  Ryder,  Para- 
mount Pictures,  Inc.,  Hollywood,  Calif. 

"Combination  16-Mm  Contact  and  Optical  Printer";  Irving  B.  Dyatt,  Oregon 
State  College. 

"A  High-Speed  Method  of  Controlling  Kelvin  and  Light  Intensity  for  Motion 
Picture  Printers";  Irving  B.  Dyatt,  Oregon  State  College. 

"Modern  Processes  of  Color  Photography";  Joseph  S.  Friedman. 

"Cunningham  Combat  Camera";  Harry  Cunningham,  RKO  Studies,  Hollywood, 
Calif.,  and  Capt.  E.  H.  Fehnders,  U.  S.  Army  Signal  Corps. 

"Improvements  in  16-Mm  Equipment";  Commander  Alfred  Gilks,  Office  of 
Strategic  Supplies,  Field  Photographic  Branch. 

"The  Work  of  the  Training  Film  Branch,  Photographic  Division,  Bureau  of  Aero- 
nautics, U.  S.  Navy";  Lt.  Orville  Goldner,  U.  S.  N.  R.,  Washington,  D.  C. 

"Production  Planning  for  Navy  Training  Films";    Lt.  R.  B.  Lewis. 


268 


FIFTY-FOURTH  SEMI-ANNUAL  CONFERENCE 


"Making  Films  That  Teach";   Lt.  Reginald  Bell,  Training  Film  Branch,  Bureau 

of  Aeronautics,  U.  S.  Navy. 
"The  Training  Film  Program  in  Action";    Training  Film  Branch,  Fire  Control 

School,  Navy  Yard,  Washington,  D.  C. 


IMPORTANT 

Hotel  reservation  cards  must  be  re- 
turned immediately.  Otherwise  the 
Hotel  cannot  guarantee  accommoda- 
tions. 


Members  intending  to  attend  the  Fifty-Fourth  Semi- Annual  Confer- 
ence should  make  arrangements  for  their  railroad  accommodations  im- 
mediately or  at  the  latest  one  and  a  half  months  in  advance  of  the  Con- 
ference date. 


SOCIETY  ANNOUNCEMENTS 


AMENDMENTS  OF  THE  BY-LAWS 

At  the  meeting  of  the  Board  of  Governors  held  at  Hollywood  on  June  4th  the 
following  proposed  amendments  of  the  By-Laws  were  approved  for  submittal 
to  the  membership  of  the  Society  for  voting  at  the  Fifty-Fourth  Semi-Annual 
Technical  Conference,  to  be  held  at  Hollywood  October  18th  to  22nd,  inclusive. 

Proposed  Amendment  of  By-Law  IV,  Sec.  4(b) 

To  the  list  of  standing  Committees  appointed  by  the  Engineering  Vice-President 
shall  be  added  the  Committee  on  Test- Film  Quality. 

Proposed  Amendment  of  By-Law  IV,  Sec.  5 

Two  Admissions  Committees,  one  for  the  Atlantic  Coast  Section  and  one  for 
the  Pacific  Coast  Section,  shall  be  appointed.  The  former  Committee  shall 
consist  of  a  Chairman  and  six  Fellow  or  Active  members  of  the  Society,  residing 
in  the  metropolitan  area  of  New  York,  of  whom  at  least  four  shall  be  members  of 
the  Board  of  Governors. 

The  latter  Committee  shall  consist  of  a  Chairman  and  four  Fellow  or  Active 
members  of  the  Society  residing  in  the  Pacific  Coast  area,  of  whom  at  least  three 
shall  be  members  of  the  Board  of  Governors. 

MAILING  OF  NOTICES  TO  MEMBERS  OF  THE 
ATLANTIC  COAST  SECTION 

As  the  territory  included  by  the  Atlantic  Coast  Section  of  the  Society  extends 
from  Maine  to  Florida  and  includes  the  Eastern  and  Central  Standard  Time 
zones  (as  the  result  of  the  discontinuance  of  the  Mid-West  Section),  many  of  the 
members  of  the  Section  find  it  impossible  to  attend  the  monthly  meetings  and 
other  functions.  The  situation  has  been  considerably  aggravated  by  the  present 
difficulties  of  transportation. 

For  these  reasons,  as  well  as  for  reasons  of  economy,  the  Board  of  Governors, 
at  the  meeting  held  on  May  3rd  at  New  York,  felt  that  notices  of  meetings, 
routine  letters,  and  other  material  should  be  sent  only  to  members  of  the  Section 
residing  in  the  New  York  metropolitan  area,  since  it  is  from  this  area  that  the 
meetings  draw  practically  all  their  attendance. 

However,  the  Board  provided  also  that  members  not  residing  in  the  New  York 
metropolitan  area  but  who  wish  to  receive  such  notices,  etc.,  may  have  their  names 
continued  upon  the  mailing  list  of  the  Section  by  writing  to  the  office  of  the 
Society,  at  the  Hotel  Pennsylvania,  New  York,  N.  Y. 


269 


S.  M.  P.  E.  TEST-FILMS 


These  films  have  been  prepared  under  the  supervision  of  the  Projection 
Practice  Committee  of  the  Society  of  Motion  Picture  Engineers,  and  are 
designed  to  be  used  in  theaters,  review  rooms,  exchanges,  laboratories, 
factories,  and  the  like  for  testing  the  performance  of  projectors. 

Only  complete  reels,  as  described  below,  are  available  (not  short  sections 
or  single  frequencies).  The  prices  given  include  shipping  charges  to  all 
points  within  the  United  States;  shipping  charges  to  other  countries  are 
additional. 

35-Mm.  Sound-Film 

Approximately  500  feet  long,  consisting  of  recordings  of  several  speak- 
ing voices,  piano,  and  orchestra;  buzz-track;  fixed  frequencies  for  focus- 
ing sound  optical  system;  fixed  frequencies  at  constant  level,  for  de- 
termining reproducer  characteristics,  frequency  range,  flutter,  sound- 
track adjustment,  60-  or  96-cycle  modulation,  etc. 

The  recorded  frequency  range  of  the  voice  and  music  extends  to  10,000 
cps. ;  the  constant-amplitude  frequencies  are  in  15  steps  from  50  cps.  to 
10,000  cps.  Price  $37.50  each. 

35-Mm.  Visual  Film 

Approximately  500  feet  long,  consisting  of  special  targets  with  the  aid 
of  which  travel-ghost,  marginal  and  radial  lens  aberrations,  definition, 
picture  jump,  and  film  weave  may  be  detected  and  corrected.  Price 
$37.50  each. 

16-Mm.  Sound-Film 

Approximately  400  feet  long,  consisting  of  recordings  of  several  speak- 
ing voices,  piano,  and  orchestra;  buzz-track;  fixed  frequencies  for  focus- 
ing sound  optical  system;  fixed  frequencies  at  constant  level,  for  de- 
termining reproducer  characteristics,  frequency  range,  flutter,  sound- 
track adjustment,  60-  or  96-cycle  modulation,  etc. 

The  recorded  frequency  range  of  the  voice  and  music  extends  to  6000 
cps.;  the  constant-amplitude  frequencies  are  in  11  steps  from  50  cps.  to 
6000  cps.  Price  $25.00  each. 

16-Mm.  Visual  Film 

An  optical  reduction  of  the  35-mm.  visual  test-film,  identical  as  to 
contents  and  approximately  225  feet  long.  Price  $25.00  each. 

SOCIETY  OF  MOTION  PICTURE  ENGINEERS 

HOTEL  PENNSYLVANIA 

NEW  YORK,  N.  Y. 


JOURNAL  OF  THE  SOCIETY  OF 
MOTION   PICTURE   ENGINEERS 

VOLUME  XLI  •         •          •         OCTOBER,  1943 


CONTENTS 

PAGE 

The  General  Electric  Television  Film  Projector 

E.  D.  COOK    273 

Report  of  the  Committee  on  Sound  292 

A  Note  on  the  Projection  Life  of  Film 

D.  R.  WHITE  AND  C.  DEMoos    297 

Some  Characteristics  of  Ammonium  Thiosulfate  Fixing 
Baths  D.  B.  ALNUTT    300 

The  Motion  Picture  in  the  Service  of  the  Army  Air  Forces 

L.  CARR    329 

A  Compact  Production  Unit  for  Specialized  Film 

O.  W.  HUNGERFORD      332 

Discussion  of  Industry  Problems  E.  KUYKENDALL    336 

Some  Suggested  Standards  for  Direct  16-Mm  Production 

L.  THOMPSON    340 

Resistance  of  Glass  to  Thermal  SJiock       C.  D.  OUGHTON    351 
Current  Literature  358 

The  Fifty-Fourth  Semi-Annual  Technical  Conference  of 
the  Society,  Hollywood,  Calif.,  October  18-22,  1943  360 

(The  Society  is  not  responsible  Jor  statements  of  authors.) 


JOURNAL  OF  THE  SOCIETY  OF 
MOTION  PICTURE  ENGINEERS 

HARRY  SMITH,  JR.,  EDITOR 
ARTHUR  C.  DOWNES,  Chairman 

Board  of  Editors 

JOHN  I.  CRABTREE      ALFRED  N.  GOLDSMITH       EDWARD  W.  KELLOGG 
CLYDE  R.  KEITH       ALAN  M.  GUNDELFINGER     CHARLES  W.  HANDLE Y 

ARTHUR  C.  HARDY 
Officers  of  the  Society 
**  President:  HERBERT  GRIFFIN, 

90  Gold  Street,  New  York,  N.  Y. 
"Past-President:  EMERY  HUSE, 

6706  Santa  Monica  Blvd.,  Hollywood,  Calif. 
** 'Executive  Vice-President:  LOREN  L.  RYDER, 
5451  Marathon  Street,  Hollywood,  Calif. 
*Engineering  Vice-President:  DONALD  E.  HYNDMAN, 

350  Madison  Avenue,  New  York,  N.  Y. 
** Editorial  Vice-President:  ARTHUR  C.  DOWNES, 

Box  6087,  Cleveland,  Ohio. 
* Financial  Vice-President:  ARTHUR  S.  DICKINSON, 

28  W.  44th  Street,  New  York,  N.  Y. 
**Convention  Vice-President:  WILLIAM  C.  KUNZMANN, 

Box  6087,  Cleveland,  Ohio. 
^Secretary:  E.  ALLAN  WILLIFORD, 

30  E.  42nd  Street,  New  York,  N.  Y. 
^Treasurer:  M.  R.  BOYER, 

350  Fifth  Ave.,  New  York,  N.  Y. 
Governors 

*H.  D.  BRADBURY,  411  Fifth  Avenue,  New  York,  N.  Y. 
*FRANK  E.  CARLSON,  Nela  Park,  Cleveland,  Ohio. 
*ALFRED  N.  GOLDSMITH,  580  Fifth  Avenue,  New  York,  N.  Y. 
*A.  M.  GUNDELFINGER,  2800  S.  Olive  St.,  Burbank,  Calif. 
*CHARLES  W.  HANDLEY,  1960  W.  84th  Street,  Los  Angeles,  Calif. 
*EDWARD  M.  HONAN,  6601  Romaine  Street,  Hollywood,  Calif. 
*JOHN  A.  MAURER,  117  E.  24th  Street,  New  York.  N.  Y. 
**WILLIAM  A.  MUELLER,  Burbank,  Calif. 

**HOLLIS  W.  MOYSE,  6656  Santa  Monica  Blvd.,  Hollywood,  Calif. 
**H.  W.  REMERSHIED,  716  N.  La  Brea  St.,  Hollywood,  Calif. 
** JOSEPH  H.  SPRAY,  1277  E.  14th  Street,  Brooklyn,  N.  Y. 
**REEVE  O.  STROCK,  195  Broadway,  New  York,  N.  Y. 

*Term  expires  December  31,  1943. 
**Term  expires  December  31,  1944. 


Subscription  to  non-members,  $8.00  per  annum;  to  members,  $5.00  per  annum,  included 
in  their  annual  membership  dues;  single  copies,  $1.00.  A  discount  on  subscription  or  single 
copies  of  15  per  cent  is  allowed  to  accredited  agencies.  Order  from  the  Society  of  Motion 
Picture  Engineers,  Inc.,  20th  and  Northampton  Sts.,  Easton,  Pa.,  or  Hotel  Pennsylvania,  New 
York,  N.  Y. 

Published  monthly  at  Easton,  Pa.,  by  the  Society  of  Motion  Picture  Engineers. 

Publication  Office,  20th  &  Northampton  Sts.,  Easton,  Pa. 

General  and  Editorial  Office,  Hotel  Pennsylvania,  New  York,  N.  Y. 

Entered  as  second-class  matter  January  15,  1930,  at  the  Post  Office  at  Easton, 

Pa.,  under  the  Act  of  March  3,  1879.     Copyrighted,  1943,  by  the  Society  of  Motion 

Picture  Engineers,  Inc. 


Frank  H.  Richardson 


As  the  October  Journal  goes  to  press  we  learn  with  sorrow  of 
the  death  of  Frank  H.  Richardson,  Fellow  of  the  Society  and  a 
member  since  its  founding  in  1916.  We  have  lost  a  loyal  and 
active  associate  whose  devoted  interest  in  the  welfare  of  the  Society 
will  long  be  remembered. 


The  Society  of  Motion  Picture  Engineers 

Its  Aims  and  Accomplishments 

The  Society  was  founded  in  1916,  its  purpose,  as  expressed  in  its 
Constitution,  being  the  "advancement  in  the  theory  and  practice  of 
motion  picture  engineering  and  the  allied  arts  and  sciences,  the  stand- 
ardization of  the  mechanisms  and  practices  employed  therein,  and  the 
maintenance  of  a  high  professional  standing  among  its  members." 

The  membership  of  the  Society  is  composed  of  the  technical  experts 
in  the  various  research 'laboratories  and  other  engineering  branches  of 
the  industry,  executives  in  the  manufacturing,  producing,  and  exhibit- 
ing branches,  studio  and  laboratory  technicians,  cinematographers, 
projectionists,  and  others  interested  in  motion  picture  engineering. 

The  Society  holds  two  conventions  a  year,  spring  and  fall,  at  various 
places  and  generally  lasting  four  days.  At  these  meetings  papers 
dealing  with  all  phases  of  the  industry — theoretical,  technical,  and 
practical — are  presented  and  discussed,  and  equipment  and  methods 
are  often  demonstrated.  A  wide  range  of  subjects  is  covered,  many 
of  the  authors  being  the  highest  authorities  in  their  particular  lines 
of  endeavor.  On  occasion,  special  developments,  such  as  the  SMPE 
Visual  and  Sound  Test-Films  designed  for  the  general  improvement 
of  the  motion  picture  art,  are  placed  at  the  disposal  of  the  member- 
ship and  the  industry. 

Papers  presented  at  conventions,  together  with  contributed  articles, 
translations,  and  reprints,  and  other  material  of  interest  to  the  motion 
picture  engineer  are  published  monthly  in  the  JOURNAL  of  the  Society. 
The  publications  of  the  Society  constitute  the  most  complete  existing 
technical  library  of  the  motion  picture  industry. 


THE  GENERAL  ELECTRIC  TELEVISION  FILM  PROJECTOR 
ELLSWORTH   D.  COOK** 


Summary. — In  the  following  paper,  the  General  Electric  television  motion  picture 
film  projector  is  described  by  its  designer.  Certain  of  the  design  objectives  and  some 
of  the  special  problems  involved  are  discussed.  A  mong  these  problems  is  the  projec- 
tion of  standard  motion  picture  film  at  thirty  television  frames  per  second  without 
change  in  sound  quality.  The  theory  and  construction  of  the  intermittent  movement 
are  given  and  views  are  shown  of  the  projection  equipment  as  installed  in  the  General 
Electric  Television  Station  WRGB. 

Because  of  the  great  amount  of  time  necessary  for  the  rehearsal  of 
each  new  act,  the  rapid  exhaustion  of  available  subject  material,  and 
the  general  interest  in  news  events,  it  is  thought  that  much  of  the 
subject  material  for  commercial  television  programs  will  be  obtained 
from  current  motion  picture  films  as  soon  as  widespread  use  is  made 
of  this  facility. 

The  operational  standards  chosen  for  television  have  made  it 
necessary  to  redesign  or  modify  existing  motion  picture  projection 
equipment,  at  least  at  the  beginning  of  television  broadcasting. 
This  condition  is  likely  to  continue  since  it  does  not  seem  practical  to 
finance  "retakes"  of  the  desired  subject  material  or  that  motion 
picture  producers  would  be  willing  to  revise  their  equipment  to  fit 
new  standards,  particularly  since  they  have  just  passed  through 
one  such  major  and  expensive  revision  in  connection  with  sound 
recording. 

The  present  standard  television  picture  is  formed  by  an  elementary 
spot  of  light  of  varying  brilliancy  moving  across  the  picture  frame 
in  parallel  lines.  Since  there  are  525  approximately  horizontal  lines 
for  each  television  picture,  and  since  the  picture  is  formed  by  first 
traversing  the  odd-numbered  lines  and  then  the  intermediate  even- 
numbered  lines,  it  is  evident  that  the  detail  of  the  picture  would 
suffer  if,  for  any  reason,  these  alternate  lines  should  overlap.  It 

*  Presented  at  the  1942  Spring  Meeting  at  Hollywood,  Calif. 
"*  General  Engineering  Laboratory  of  the  General  Electric  Company,  Sche- 
nectady,  N.  Y. 

273 


274  E.  D.  COOK  [J.  S.  M.  P.  E. 

has  been  thought  that  the  limit  of  any  displacement  between  the 
alternate  lines  should  be  equal  to  one-half  of  their  relative  spacing. 
Thus,  a  vertical  displacement  of  approximately  Vio  of  one  per  cent 
would  represent  a  practical,  superior  limit  for  any  such  motion. 
Since,  as  will  be  seen  later,  the  odd-numbered  lines  of  certain  definite, 
television  pictures  may  be  obtained  from  one  individual  frame  or 
picture  of  a  motion  picture  film,  while  the  even-numbered  lines 
may  be  obtained  from  the  following  frame,  it  will  be  evident  that  a 
logical  specification  for  the  accuracy  of  registration  of  succeeding 
pictures  thrown  upon  the  reproducing  screen  by  the  motion  picture 
projector  would  be  this  same  figure,  Vio  of  one  per  cent,  as  an  upper 
limit.  Naturally,  such  a  specification  would  assume  that  equal  ac- 
curacy will  be  found  throughout  the  entire  television  system  re- 
sponsible for  the  line  structure,  as  well  as  in  the  motion  picture 
camera  and  printer,  and  that  a  proper  film,  once  made,  could  be  main- 
tained if  such  performance  is  to  be  effectively  employed. 

A  careful  consideration  of  the  requirements  for  speed  constancy 
and  experience  with  the  possibilities  of  the  better  forms  of  me- 
chanical filters  in  this  field  reveal  that  in  the  matter  of  construction 
to  meet  the  desired  specification,  the  advantages  should  lie  with 
the  intermittent  type  of  projector  rather  than  with  the  so-called 
"continuous  motion  projector."  In  fact,  the  problem  of  film  shrink- 
age alone  would  be  sufficient  to  cause  the  experienced  designer  to 
prefer  the  former  type  of  machine. 

This  paper  is  a  description  of  the  G-E  standard  35-mm  motion 
picture  projector  development  for  television  service.  This  project 
was  started  in  March,  1938,  and  two  of  the  projectors  described 
have  been  in  use  since  December  of  that  year.  Because  of  its  de- 
sign, the  E-7  Simplex  Projector  was  chosen  and  modified  to  suit 
the  special  conditions  peculiar  to  this  field.  The  operating  side  of 
the  projector  is  shown  in  Fig.  1. 

It  has  been  standard  practice  in  television  to  use  a  frame  frequency 
which  is  a  sub-multiple  of  the  frequency  of  the  supply  voltage,  for 
instance,  30  per  second,  because  of  any  possible  residual  hum  in 
rectified  d-c  voltage  supplies.  The  present  standard  sound  motion 
picture  practice  utilizes  a  frame  frequency  of  24  per  second.  In  order 
to  bring  these  two  standards  into  agreement  so  that  standard  sound 
motion  picture  film  may  be  used,  it  is  necessary  to  employ  a  varying 
frequency  of  projection  so  that  the  average  frequency  may  remain 
24  film  frames  per  second.  This  is  possible  if  the  instantaneous 


Oct.,  1943] 


TELEVISION  FILM  PROJECTOR 


275 


projection  speed  alternates  between  30  and  20  frames  per  second  in 
such  a  manner  that  the  average  film  speed  may  remain  24  frames 
per  second. 

Since  the  slower  instantaneous  projection  frequency  would  leave 
a  given  film  frame  in  the  projection  aperture  for  a  time  interval  that 
would  be  fifty  per  cent  greater  than  that  for  the  higher  projection 


FIG.  1.     The  General  Electric  television  motion  picture  film  pro- 
jector. 

frequency,  it  will  be  evident  that  any  mechanical  movement,  which 
will  project  two  film  frames  for  each  complete  revolution  of  its  drive 
shaft  in  such  a  manner  that  each  film  frame  will  remain  in  the  pro- 
jection aperture  the  necessary  length  of  time  and  one  will  remain 
fifty  per  cent  longer  than  the  following  film  frame,  may  be  used  for 
this  purpose.  This  may  be  easily  understood  by  reference  to  Fig.  2 


276 


E.  D.  COOK 


[J.  S.  M.  P.  E. 


which  shows  the  time  cycle  of  events  in  the  standard  motion  picture 
sound-film  and  the  same  film  as  used  in  television. 

It  will  be  essential  that  the  drive  shaft  to  the  intermittent  move- 
ment in  question  rotate  at  the  same  speed  that  an  otherwise  stand- 
ard motion  picture  device  would  be  forced  to  use  to  project  two 


NUMBER 
OF 
FILM 
FRAME 

STANDARD 
SOUND 
FILM 
CYCLE 

ELAPSED]  NUMBER 

TIME      |       OF 
IN         .TELEVlSIOn 
SECONDS     FRAME 

TELEVISION  CYCLE 
FOR 
STANDARD  FILM 
WITH    7.570 
ILLUMINATION  TIME 

ELAPSED 
TIME 
IN 
SECONDS 

ILLUM. 

.OOOO 

ILLUM. 

.01  04 

DARK 

a 

DARK 

1 

SCAN 

0  1  67 

1 

.0208 

ILLUM. 

O  1  79 

ILLUM. 

.0313 

XDARK  a  SCAN// 
^         a          // 

MOVE  1  FILM  FRAME 

///n  '  L*  /.  /  /s 

0333 

//      ft     V/ 

ILLUM. 

0346 

/^MOVE.//^ 

..0417 

DARK 

ILLUM. 

.0521              2 

a 

SCAN 

.05OO 

0 

DARK 

.0625 

DARK 

a 

.05  1  3 

SCAN 

0667 

ILLUM. 

ILLUM. 

.0729 

•///r\/o    '  a?  e^  '  '  ''  / 

^0*a^ 

J0833            , 

//         a         x^ 

MOVE  1  FILM  FRAME 

3 

ILLUM. 

ILLUM. 

.0938 

DARK 

DARK 

SCAN 

1  GOO 

.1042 

ILLUM. 

1  O  1  3 

ILLUM. 

.1  146 

/'DARK  V  SCAN^ 
MOVE  1  FILM  FRAME 

.1167 

/,         OL          // 

ILLUM. 

1179 

•%MOVE/// 

.1250 

DARK 

ILLUM. 

a 

SCAN 

.1  333 

ILLUM 

1  346 

DARK 

.  1458 

DARK 

a 

5 

SCAN 

1  5OO 

ILLUM. 

ILLUM. 

1513 

!«?£! 

.  1667 

/DARK  a  S'CAN"/^/ 

MOVE  1  FILM  FRAME 

IP67 

FIG.  2. 


Time  cycle  comparison  for  motion  picture  film  in 
television  and  theater  projectors. 


film  frames  per  revolution  of  the  equivalent  shaft.  In  the  usual 
projector  (and  this  applies  to  the  standard  model  E-7  used  here)  only 
one  frame  is  projected  per  revolution.  Hence,  this  drive  shaft 
normally  revolves  at  1440  rpm. 

In  the  design  of  the  modified  machine,  this  would  call  for  the  inter- 


Oct.,  1943]  TELEVISION  FILM  PROJECTOR  277 

mittent  drive  shaft  to  operate  at  a  steady  speed  of  720  rpm  with 
projection  occurring  at  a  reference  point  and  again  144  degrees 
later  for  each  revolution;  i.  e.,  each  revolution  is  divided  into  parts 
respectively  of  2/5  and  3/5  in  duration.  Such  a  design  would  produce 
a  severe  screen  flicker  and  if  this  is  to  be  avoided,  the  number  of 
pictures  projected  per  second  would  have  to  be  increased.  This 
may  be  accomplished  if  the  viewing  time  of  such  a  sequence  of  opera- 
tions is  interrupted,  as  in  standard  motion  picture  operation. 

If  two  views  of  the  same  picture  are  to  be  seen  during  the  2/5  por- 
tion of  the  cycle,  three  views  of  the  next  film  frame  will  be  seen  dur- 
ing the  remaining  3/5  portion  of  the  cycle.  Therefore,  it  is  obvious 
that  the  intermittent  film  motion  could  not  be  permitted  to  utilize 
90  mechanical  degrees  of  the  intermittent  drive  shaft  rotation.  This 
is  important,  since  it  rules  out  the  standard  form  of  Geneva  motion. 


r  «a*  ^    n 


FIG.  3.     Disassembled  view  of  intermittent  in  General  Electric  television  pro- 
jector. 

It  was  mentioned  previously  that  in  present  television  practice 
in  the  United  States,  which  practically  presupposes  the  use  of  cath- 
ode ray  tubes,  the  picture  is  "painted"  by  a  flying  spot  of  light  of 
varying  intensity  that  moves  across  the  field  in  approximately  hori- 
zontal lines,  and  that  each  of  the  successive  elementary  pictures  is 
composed  of  the  alternate  lines,  respectively.  This  succession  of 
events  occurs  in  such  a  way  that  these  elementary  pictures  follow 
one  another  at  a  rate  of  60  per  second,  being  interlaced  with  a  maxi- 
mum time  interval  of  eight  per  cent  between  them,  according  to  the 
present  standards.  It  is  within  this  short  time  interval  that  the 
film  will  be  illuminated,  and  if  a  blurred  picture  is  to  be  avoided, 
the  film  must  be  at  rest  during  the  period  of  illumination. 

Thus,  the  complete  operation  for  each  individual  or  elementary 
television  picture  must  be  confined  to  72  degrees  of  mechanical  ro- 
tation of  the  intermittent  drive  shaft,  while  the  motion  of  the  film 


278  E.  D.  COOK  [j.  S.  M.  P.  E. 

at  the  projection  aperture  must  be  completed  in  66.24  degrees  of 
rotation  of  this  same  shaft,  if  the  projector  is  to  be  synchronized 
with  the  flying  spot.  One  of  the  simplest  movements  known  that 
can  operate  with  this  reduced  angle  of  motion  and  give  a  high  degree 
of  registration,  is  the  Powers  movement.  This  is  essentially  a  face 
cam.  The  intermittent  sprocket  shaft  terminates  in  a  plate  with 
four  pins  located  on  a  square  so  that  two  slide  on  the  outer  cam 
surface  and  two  slide  on  the  inner  cam  surface.  A  disassembled 
view  of  the  intermittent  movement  may  be  seen  in  Fig.  3.  The 
principle  is  covered  by  the  patent  issued  to  A.  V.  Bedford  (U.  S. 
2,082,093). 

It  is  noted  that  the  drive  shaft  and  cam  wheel  operate  in  the 
same  direction  for  outside  cams  which  were  preferred  in  this  case. 
Since  the  relative  of  these  two  parts  is  the  reverse  of  the  Geneva 
motion,  which  it  will  now  replace,  the  direction  of  the  cam  shaft 
would  have  to  be  reversed.  It  was  found  possible  to  add  an  idler 
gear  inside  the  intermittent  casting  to  accomplish  this.  The  theory 
of  design  for  the  Powers  cam  will  be  explained  later. 

Since  the  television  picture  has  60  elementary  views  per  second, 
it  is  evident  that  the  shutter  speed  must  be  modified  to  synchronize 
it  with  the  film  cycle.  The  permitted  speeds  are  sub-multiples  of 
3600  rpm. 

If  the  shutter  shaft  is  to  remain  in  its  present  position,  the  ad- 
vantages of  larger  shutter  diameters  are  not  available.  Based  on  a 
given  percentage  of  time  allotted  to  the  illumination  of  the  film  in  a 
given  shutter  system,  the  size  of  the  shutter  opening  is  determined 
by  the  shutter  speed.  If  the  shutter  opening  is  smaller  than  the 
diameter  of  the  cone  of  light  at  the  shutter  plane,  it  becomes  a  limita- 
tion on  the  amount  of  light  that  can  be  passed  by  the  optical  system. 
Hence,  it  is  an  advantage  in  a  disk  shutter  to  use  a  single  aperture 
and  operate  at  3600  rpm.  In  this  case,  it  was  found  that  for  the 
diameter  of  shutter  which  can  be  accommodated,  the  shutter  was  the 
limiting  aperture.  In  spite  of  this,  calculation  and  subsequent 
experience  have  revealed  that  ample  margin  in  illumination  is  avail- 
able for  the  iconoscope. 

The  shutter  aperture,  as  originally  chosen,  was  seven  per  cent, 
hence  the  remainder  of  the  time  allowed  for  the  television  spot  to 
pass  through  one  vertical  retrace  operation  is  available  to  overcome 
any  mechanical  trouble  due  to  back-lash  or  transients  which  might 
exist  in  any  other  part  of  the  equipment. 


Oct.,  1943]  TELEVISION  FILM  PROJECTOR  279 

The  E-7  Simplex  projector  is  normally  equipped  with  1440  rpm 
front  and  rear  shutters.  In  normal  motion  picture  operation,  this 
design  permits  greater  illumination  on  the  screen  and  a  cooler  film. 
The  rear  shutter  was  originally  equipped  with  a  fan.  The  fan  was 
omitted  in  the  modified  design,  employing  3600  rpm  shutters  be- 
cause of  the  excessive  power  requirements.  Fortunately,  heating 
is  not  a  problem  in  the  projector  optical  system  for  television  service. 

With  the  new  intermittent  motion,  space  limitations  would  have 
prevented  as  much  framing  correction  as  permitted  in  the  standard 
E-7  Simplex  projector,  but  the  primary  reason  for  this  adjustment 
has  largely  disappeared  in  first-class  projection  rooms.  Its  inclusion 
in  a  standard  projector  is  due  primarily  to  the  fact  that  certain 


FIG.  4.     Disassembled  view  of  shutter-shaft  driving  system  for  General  Elec- 
tric television  projector. 

theaters,  which  may  purchase  new  projectors,  often  receive  film 
which  is  badly  mutilated  or  hire  operators  who  frequently  do  not 
attempt  to  maintain  the  careful  projection  practice  demanded  in 
higher  grade  theaters. 

The  use  of  the  framing  adjustment  is  dependent  upon  careless- 
ness, either  in  the  splicing  or  the  inspection  of  the  film  before  "run- 
ning" a  show  or  in  "threading."  Television,  as  a  new  industry  in 
which  each  transmitter  hopes  to  reach  thousands  of  observers,  can 
hardly  expect  to  employ  operators  who  are  less  careful  than  those 
of  the  better  theaters.  "Threading"  mistakes  would  be  pure  care- 
lessness with  both  a  framing  and  a  threading  lamp  especially  pro- 
vided to  make  inspection  of  framing  a  simple  matter  during  thread- 


280 


E.  D.  COOK 


[J.  S.  M.  P.  E. 


ing.  Furthermore,  television  should  not  countenance  the  use  of 
film  so  badly  mutilated  that  missing  sprocket  holes  permit  the  pic- 
ture to  get  out  of  frame  after  being  correctly  threaded ;  in  fact,  it  is 
likely  that  the  television  studio  will  insist  on  first-run  film  because 
of  the  very  serious  loss  in  definition  that  will  exist  for  even  the  smallest 
wear  at  the  sprocket-holes  or  abrasion  of  the  film.  The  former  point 
will  be  more  fully  appreciated  when  it  is  realized  that  a  vertical  dis- 


FIG.  5. 


Skeleton  assembly  view  of  shutter-shaft  driving  system 
for  General  Electric  television  projector. 


placement  of  the  film  in  the  projection  aperture  of  only  0.0014  inch 
from  its  correct  position  is  equivalent  to  a  shift  in  the  television 
picture  of  one  scanning  line  pitch.  Such  motion  is  twice  the  limit 
previously  mentioned  as  a  desirable  upper  limit. 

A  direct  drive  from  the  main  drive  shaft  to  the  shutter  shaft  was 
used  in  order  to  relieve  the  projector  gears  and  stud  shafts  of  the 
shutter  load,  and  to  reduce  the  possibility  of  excessive  speed  variation 
in  the  shutter  motion  that  would  otherwise  exist  due  to  back-lash  in 


Oct.,  1943]  TELEVISION  FILM  PROJECTOR  281 

the  gear  train.  These  two  factors  were  found  to  be  of  considerable 
importance.  Since  the  motor  operates  at  1800  rpm,  a  two-to-one 
increase  in  speed  was  made  necessary  by  the  use  of  the  3600  rpm 
shutter. 

Experience  showed  that  this  design,  in  addition  to  improving  the 
safety  factor  on  the  projector  gears,  permitted  quieter  operation 
than  would  have  been  possible  with  any  back-geared  arrangement 
on  the  original  shutter  shaft,  and  permitted  rapid  starting  time 
Experience  has  also  shown  that  with  the  direct  shutter  drive  it  re- 
quires about  three  to  four  seconds  to  synchronize  fully  the  motor 
with  the  line,  but  it  is  conceivable  that  this  may  vary  somewhat. 

In  order  to  accomplish  this,  two  things  were  necessary:  (1)  the 
original  shutter-shaft  drive  gear  on  the  oblique  shaft  in  the  picture 
head  was  removed  and  (2)  a  special  sound  head  drive  shaft  with  an 
extension  on  the  coupling  end  was  employed.  The  latter  permitted 
a  vertical  shaft  to  be  located  just  in  front  of  the  sound-head  and 
projector  casting.  A  special  adapter  was  fastened  to  the  sound- 
head  gear  box.  This  was  designed  to  employ  a  ball  bearing  to  sup- 
port the  sound-head  drive  shaft  adjacent  to  the  one-to-two  spiral 
gears  that  were  used  to  drive  the  vertical  shutter  shaft  from  the 
sound-head  drive  shaft.  These  gears  were  hardened  and  designed 
to  operate  in  an  oil  bath.  The  component  parts  used  to  drive  the 
shutter  shaft  by  means  of  an  external  drive  shaft  are  shown  in 
Fig.  4,  and  a  skeleton  assembly  of  these  parts  is  shown  in  Fig.  5. 

A  spacing  bracket  was  fastened  between  the  sound-head  and  the 
usual  motor  base  bracket  to  accommodate  the  gear  box  for  the 
vertical  shaft.  The  flexible  coupling  originally  employed  between 
the  motor  and  the  sound-head  drive  shaft  was  used  as  before. 

The  splined  gear  and  the  spline  assembly  found  on  the  original 
shutter  shaft  were  removed,  and  an  adapter  was  added  to  fit  within 
the  existing  spline  housing  that  is  bolted  to  the  main  projector 
frame.  An  extended  shutter  bearing  housing,  as  shown  in  Fig.  5, 
was  designed  to  pass  through  the  front  casting  of  the  projector 
head  and  clamp  in  this  adapter.  This  established  a  rigid  front 
support  for  the  shutter  shaft  by  the  use  of  two  sealed  ball  bearings 
at  the  front  shutter  end  of  this  extended  bearing  housing  and,  like- 
wise, accommodated  a  ball  bearing  for  the  upper  end  of  the  3600- 
rpm  vertical  shutter  drive  shaft.  Hardened  spiral  gears,  operating 
in  an  oil  bath,  were  used  between  the  vertical  drive  and  the  shutter 
shafts.  The  ratio  of  speeds  at  this  point  was  one-to-one.  Special 


282 


E.  D.  COOK 


[J.  S.  M.  P.  E. 


attention  has  been  given  to  means  of  preventing  the  rapid  leakage  of 
oil  from  the  oil  wells  at  each  end  of  the  vertical  shaft.  Oil  cups 
were  added  to  make  daily  inspection  and  filling  of  these  oil  wells  to 
the  proper  level  a  simple  matter. 

Several  additional  considerations  of  a  minor  nature  will  be  found 
in  the  problem  of  adapting  the  E-7  Simplex  projector  to  television 
service;  for  example,  the  iconoscope  screen  position  and  the  toler- 
ances in  its  size  forced  the  use  of  a  longer  focal  length  lens  than  is 
ordinarily  used.  The  lens  chosen  for  this  purpose  was  provided 


FIG.  6.     Driving  gear  system  for  General  Electric  television  pro- 
jector. 

with  a  reduced  rear-barrel  diameter.  Therefore,  a  special  adapter 
was  required  in  the  rear  lens  mount  to  clamp  that  portion  of  the  pro- 
jection lens  which  had  a  reduced  diameter. 

The  projection  lens  should  place  an  image  of  the  rear  shutter  on 
the  front  shutter,  if  the  latter  is  to  cut  off  all  of  the  remaining  light 
passed  by  the  rear  shutter  when  both  have  their  corresponding 
aperture  edges  on  the  optical  axis.  The  preliminary  design  cal- 
culations indicated  that  an  exact  focus  would  require  an  impractical 
extension  of  the  front  end  of  the  shutter  shaft.  However,  since  the 
image  of  the  rear  shutter  aperture  edge  produced  by  the  projection 


Oct.,  1943] 


TELEVISION  FILM  PROJECTOR 


283 


lens  was  not  too  poor  at  the  present  front  shutter  position,  and  since 
some  margin  in  closing  time  exists,  no  modification  was  felt  de- 
sirable. Tests  on  the  finished  machine  showed  acceptable  per- 
formance for  both  the  opening  and  closing  operation  of  these  shutters 
as  far  as  they  were  affected  by  focus  of  one  upon  the  other. 

In  order  to  prevent  accidents,  the  front  shutter  housing  apertures 
were  covered  with  glass.  Although  this  is  not  done  in  professional 
use,  it  was  thought  desirable  here  in  spite  of  the  extra  glass  to  air 
surfaces  in  the  optical  path.  These  windows  also  aid  slightly  in 


FIG.  7.     Diagram  showing  geometry  of  intermittent  cam  system. 

noise-reduction.  Although  the  loss  of  light  is  not  serious,  there  is 
a  small  amount  of  scattered  light  due  to  reflection  at  these  surfaces. 
For  this  reason,  they  have  been  made  removable. 

Another  optical  problem  was  found  in  the  attempt  to  focus  accu- 
rately the  projection  lamp  on  the  projection  lens.  This  was  due  to 
the  diameter  of  the  lamp  bulb.  Since  operating  results  have  shown 
that  a  satisfactorily  uniform  field  of  illumination  could  be  obtained 
at  the  iconoscope  mosaic,  no  change  in  the  standard  condenser  sys- 
tem was  felt  necessary. 

It  was  said  that  for  average  lighting  in  normal  operation  at  least 


284  E.  D.  COOK  [J.  S.  M.  P:  E. 

25  foot-candles  would  be  required  on  the  iconoscope  mosaic,  but 
subsequent  advice  from  the  manufacturer  of  the  iconoscope  stated 
that  "satisfactory  operation  should  be  possible  with  a  level  of  1.5 
millilumens  per  square  centimeter  for  average  conditions,  and  3.5 
millilumens  per  square  centimeter  for  high  light  conditions."  Cal- 
culations showed  that  the  900-watt,  T-20  projector  lamp  was  ca- 
pable of  supplying  this  level  under  ordinary  film  conditions  with  at 
least  a  two-to-one  safety  factor.  Subsequent  measurements  con- 
firmed this.  It  was  to  make  this  possible  that  the  3600-rpm  shutter 
was  originally  chosen.  The  alternative  would  have  been  an  arc 
lamp,  since  incandescent  sources  of  higher  illumination  were  not 
available. 


FIG.  8.     Assembly  view  of  intermittent  for  General  Electric  tele- 
vision projector. 


Measurements  of  the  mechanical  power  requirements  showed  that 
a  rating  of  approximately  1/8  hp  would  be  required.  A  3-phase, 
220-volt,  self-synchronous  motor  of  this  rating  was  used.  With 
the  larger  motor,  the  moment  of  inertia  of  the  flywheel  was  increased 
to  reduce  the  shock  due  to  starting  acceleration,  as  well  as  any 
possible  effects  of  shocks  from  the  power  system. 

To  further  reduce  the  starting  acceleration,  adjustable  10-ohm  pro- 
tective resistors  were  used  in  each  of  the  3-phase  lines.  To  make 
certain  that  full-line  voltage  would  not  be  applied  to  the  motor  too 
soon,  a  time  delay  relay  and  contactor  are  used  to  short  circuit  the 
line  resistors  after  the  motor  is  synchronized  with  the  line  supply. 


Oct.,  1943] 


TELEVISION  FILM  PROJECTOR 


285 


However,  should  this  relay  fail  to  short  the  line  resistors,  no  loss  of 
synchronism  will  result. 

The  synchronous  motor  was  equipped  with  a  d-c  field  winding  of 
approximately  150  ampere  turns  per  pole  to  automatically  phase 
the  projector  with  the  electrical  power  system  and,  hence,  the  elec- 
trical impulses  used  to  effect  scanning. 

As  a  final  modification,  means  for  anchoring  the  outer  end  of  the 
stud  shafts  on  both  the  main  drive  gear  and  the  coupling  gear,  be- 
tween the  sound-head  and  the  projector,  has  been  provided.  This 
may  be  seen  from  Fig.  6  which  shows  the  gear  train  of  the  projector 
and  sound-head. 

Since  it  was  found  possible  to  use  the  main  casting  of  the  Geneva 
intermittent  system  in  which  the  distance  between  the  sprocket 
shaft  (which  was  coaxial  with  the  drive  shaft)  and  the  cam  shaft 
was  0.7495  inch,  one  dimension  b  (Fig.  7)  of  the  Power's  intermittent 


IZOV 


FIG.  9. 


TRANSFORMER 
15  X 


Schematic  connection  diagram  for  projection  lamp  in  General 
Electric  television  projector. 


was  determined.  As  a  trial,  the  distance  5  between  the  centers  of 
the  locking  pins  was  chosen  as  an  even  dimension,  but  was  later 
changed  to  improve  the  design. 

It  was  decided  to  employ  a  sine  wave  accelerating  motion  of  the 
film,  primarily  because  the  angle  of  pull-down  was  less,  in  this  case, 
than  in  the  standard  Geneva  intermittent;  and  secondarily,  to 
reduce  any  effect  of  film  motion  that  might  be  revealed  by  slightly 
incorrect  adjustments  in  the  shutter,  as  well  as  back-lash  in  drive 
gears.  Thus,  the  velocity  of  the  sprocket  shaft  would  be  slow  during 
the  beginning  and  ending  phases  of  this  motion,  but  the  cam  would 
be  called  upon  to  work  hardest  in  the  middle  of  the  moving  cycle. 

Design  of  the  Intermittent  Movement.  —  If  two  film  frames  are  re- 
quired for  one  revolution  of  the  cam  shaft  then,  as  previously  ex- 
plained, only  144  degrees  can  be  allotted  to  the  shortest  cycle,  and  if 
this  frame  of  film  is  to  be  shown  twice  during  this  time  with  a  maxi- 


286 


E.  D.  COOK 


[J.  S.  M.  P.  E. 


mum  allowance  of  eight  per  cent  for  the  upper  limit  of  time  of  illu- 
mination, the  central  angle  of  the  cam  allotted  to  film  motion  can  be 
only  66.24  degrees.  Therefore,  if  (w)  is  the  displacement  of  the 
cam  wheel  and  (a)  is  the  angular  displacement  per  cycle  of  an  inter- 
mittent sprocket  that  accommodates  four  film  frames  per  revolution, 
it  can  be  seen  that  for  sine  wave  film  motion  (see  Fig.  7) : 


or 


a  =  45  [1  -  cos  (2.7173)] 


(1} 


TO  PROJECTOR 


Hf\ND 

WHEEL. 


5WITCH  " 

ON  PROJECTOR 

PEDESTAL. 


FIELD  TO  BE  05E.D 
DURING   SYCHRONIZING 
TIME    ONLY. 


CONTACTOR   CR-3.&U-C2D 
CAT.  43SG931GIO3  WITH 
CO\L  CONNECTED    AS   SHOWN. 


FIG.  10.     Schematic  connection  diagram  of  motor  starting  circuit  for 
General  Electric  television  projector. 


Hence 


0  =  (45+  a) 
ft  =  (45  -  a) 


Once  5  is  chosen,  it  is  obvious  that 


(2} 


(3} 


In  the  design,  the  diameter  of  the  pins  d  was  chosen  as  0.1000 
inch.     The  outer  radius  of  the  cam  wheel  RI  can  be  determined  from 


and  the  inside  radius  R*  may  be  calculated  from  eq.  5 


+  »-*>  + 


(4) 


(5) 


Oct.,  1943] 


TELEVISION  FILM  PROJECTOR 


287 


The  design  of  the  actuating  surfaces  of  the  cam  involves  the  re- 
peated solution  of  eqs.  6  and  7  for  small  increments  of  displacement 
Aw,  in  this  case  1  degree  each 


cos  0 


FIG.  11. 


Motor  starting  equipment  for  General  Electric  television 
projector. 


+  b*  +  V%Sb  cos  0 


(7) 


To  complete  the  design  of  the  cam  wheel  the  other  coordinates 
for  both  TI  and  r4  must  be  calculated.  This  may  be  accomplished 
by  determining  the  included  angle  X  between  these  two  vectors, 
then  the  angle  between  either  and  the  central  vector  b,  for  ex- 
ample, 5. 


288 
Thus 


E.  D.  COOK 


5i  =  arc  cos 


[J.  S.  M.  P.  E. 
(*) 

(3) 


From  these  equations  all  of  the  necessary  details  for  the  construc- 
tion of  the  cam  wheel  and  pin  wheel  can  be  obtained. 
The  completed  cams  worked  very  well  requiring  no  more  power 


PMOTi* 


EXTERNAL.  WIRING. 

rLOW  CAPAOTY  CABLE". 

ELECTR.IC  CC-LU  TRANS  Fo^Me»?.  (RXA-CAT. 


5oo  OHM  UINE 


use 

ACROSS    PHOTO  ei_ec.TRic. 
ecu.  »ATTe«Y    IP 
urxvos  ARE    L^>H 


3o  VOLTS 


FIG.  12.     Schematic  connection  diagram  for  sound  system  in  Gen- 
eral Electric  television  projector. 

than  the  intermittent  system  they  replaced,  and  producing  a  screen 
picture  of  exceptional  steadiness.  An  assembled  view  of  the  inter- 
mittent movement  may  be  seen  in  Fig.  8. 

The  Sound  Head.  —  The  sound-head  used  was  the  Simplex  design 
employing  the  RCA  Rotary  Stabilizer.  It  utilizes  a  single  stage 
of  mechanical  filtering  to  reduce  the  variations  in  film  velocity, 
at  the  sound  scanning  point,  to  an  acceptable  amount.  Since  this 
device  has  been  previously  described  before  the  Society,  no  further 


Oct.,  1943] 


TELEVISION  FILM  PROJECTOR 


289 


description  will  be  given  here.  For  the  mathematical  theory  the 
reader  may  refer  to  a  previous  article  by  the  author,  "The  Technical 
Aspects  of  the  High-Fidelity  Reproducer"  (J.  Soc.  Mot.  Pic.  Eng., 
XXV  (Oct.,  1935),  p.  289). 

The  operation  of  this  form  of  sound-head  has  been  very  satis- 


FIG.  13.     Film  projection  room  in  General  Electric  television  Studio 

WRGB. 


factory.  Although  better  designs  are  possible,  it  was  felt  that  the 
economy  of  commercially  available  devices  more  than  offsets  the 
difference  in  performance. 

The  only  modification  necessary  was  to  have  the  sound-head 
supplied  with  the  special  shaft  previously  mentioned  having,  in 
addition,  the  proper  gear  reduction  for  an  1800-rpm  or  synchronous 


290 


E.  D.  COOK 


[J.  S.  M.  P.  E. 


motor  rather  than  for  the  1750-rpm  induction  motor  generally  sup- 
plied. The  adapter,  etc.,  necessary  to  drive  the  vertical  shaft  geared 
to  the  shutter  shaft  has  been  previously  described. 

Electrical  Features. — The  filament  of  the  projection  lamp  is  sup- 
plied from  a   step-down    transformer    and  preferably    should    be 


Fic.j]14.     Television  film  camera  room  in  General  Electric  television 
Studio  WRGB. 


brought  to  normal  voltage  (30  volts)  slowly.  There  are  several 
methods  by  which  this  may  be  accomplished,  but  a  simple  variable 
series  resistance  of  approximately  15  ohms,  10-ampere  rating,  in  the 
primary  circuit  of  the  transformer,  seems  as  economical  and  satis- 
factory as  any.  The  wiring  diagram,  which  may  conveniently  in- 
clude the  switch  at  the  rear  of  the  projector  pedestal,  is  shown  in 


Oct.,  1943]  TELEVISION  FILM  PROJECTOR  291 

Fig.  9.  If  desired,  the  filament  transformer  may  be  mounted  within 
the  pedestal. 

Adjustable  protective  resistors  have  been  specified  in  the  220- volt 
supply  lines  for  the  3-phase  synchronous  motor.  These  resistors 
limit  the  initial  starting  voltage  to  that  just  capable  of  starting  the 
motor.  As  previously  mentioned,  a  time  delay  relay  and  contactor 
have  been  provided  to  automatically  short  circuit  these  resistors. 
The  connection  diagram  is  shown  in  Fig.  10.  A  photograph  of  the 
starting  box,  including  the  three  protective  resistors,  the  time  delay 
relay,  and  the  contactor,  is  shown  in  Fig.  11. 

A  framing  light,  which  is  used  to  determine  whether  or  not  the 
film  is  properly  framed  in  the  film  gate,  is  located  in  the  demountable 
light  shield  that  has  been  placed  between  the  rear  shutter  housing 
and  the  film  gate.  A  step-down  transformer,  120  to  6  volts,  is  used 
to  operate  this  lamp  from  any  120-volt,  60-cycle  source.  The  fram- 
ing lamp  is  controlled  by  a  nickel-plated  rod  found  just  above  the 
light  shield. 

The  framing  lamp  is  normally  raised  above  the  projection  light 
beam  during  normal  operation,  but  upon  moving  the  fire  shutter 
lift  lever  forward,  the  fire  shutter  is  raised  and  the  framing  lamp  is 
automatically  switched  on  and  swung  down  to  the  optical  axis. 
Thus,  the  film  frame  in  the  gate  will  be  illuminated  with  sufficient 
intensity  for  framing  inspection  purposes. 

Since  the  photoelectric  cell  is  to  be  transformer  coupled  to  the 
amplifier,  care  should  be  exercised  to  keep  the  electrostatic  capacity 
of  the  cable  between  the  photoelectric  cell  and  the  primary  of  the 
coupling  transformer  below  50  mmfds.  The  photoelectric  cell  trans- 
former should  therefore  be  relatively  close  to  the  projector.  Due 
to  its  well  balanced  design  and  partially  shielded  location  little,  if 
any,  stray  field  "pick-up"  will  be  experienced.  Because  of  the  rela- 
tively high  overall  gain,  the  photocell  transformer  should  be  mounted 
to  prevent  microphonic  excitation  due  to  mechanical  vibration. 
The  diagram  of  connection  is  shown  in  Fig.  12. 

The  motion  picture  projection  room  of  the  General  Electric 
Company's  television  studio,  Station  WRGB,  in  Schenectady  is 
shown  in  Fig.  13,  the  associated  camera  room,  in  Fig.  14. 


REPORT  OF  THE  COMMITTEE  ON  SOUND* 

Hollywood  sound  engineers  are  currently  devoting  the  major  part 
of  their  attention  toward  maintaining  the  present  quality  of  sound. 
Research  and  development  of  new  equipment  and  methods  have  been 
sharply  curtailed  in  some  studios  and  stopped  in  others  for  the  dura- 
tion. However,  certain  improvement  programs  are  being  carried 
forward  where  equipment  had  been  ordered  before  the  war,  and  where 
delivery  has  been  completed. 

A  number  of  major  sound  development  projects,  which  had  been 
started  before  the  war,  have  been  set  aside  for  the  duration.  These 
projects  include  further  work  on  stereophonic  sound,  control  track 
recording,  multiple  horn  systems,  etc. 

Economies. — Considerable  attention  has  been  given  to  further 
economies  in  operating  techniques  and  toward  the  conservation  of 
strategic  materials.  The  preselection  of  both  picture  and  sound  takes 
is  being  widely  employed.  By  this  preselection  operation  only  the 
takes  which  are  to  be  printed  are  sent  to  the  laboratory  for  develop- 
ment, thereby  saving  considerable  quantities  of  chemicals  in  the 
developing  solutions.  Since  only  one  side  of  the  sound  negative  stock 
has  been  exposed  the  non-print  out-takes  are  reassembled  into  1000- 
ft  rolls,  reversed,  and  the  unexposed  edge  of  this  film  used  for  daily 
sound  prints,  leader  stock,  and  other  uses.  Split  film  is  another 
method  used  for  the  conservation  of  film. 

The  use  of  dry  batteries  has  been  markedly  reduced  by  the  conver- 
sion of  plant  equipments  to  a-c  operation. 

Vacuum  tube  types  have  also  been  standardized  in  many  equip- 
ments. 

The  following  paragraphs  outline  a  number  of  the  features  of  a 
typical  Hollywood  sound-recording  channel  as  used  today : 

Microphone. — Directional  type  microphones  are  being  more  widely 
used  to  reduce  pick-up  from  extraneous  noise  sources  and  to  reduce 
acoustic  pick-up  difficulties  inherent  in  wartime  set  construction. 

Microphone  Booms  and  Poles. — The  present  trend  is  to  use  lighter 
weight  and  more  portable  booms.  The  gunning  devices  have  been 

*  Presented  at  the  1943  Spring  Meeting  at  New  York. 
292 


REPORT  OF  SOUND  COMMITTEE  293 

improved  and  have  made  easier  the  operation  of  placing  the  direc- 
tional microphone.  The  use  of  the  "fish-pole"  type  of  mike  boom 
has  increased  in  recent  years.  This  type  of  microphone  pole  consists  of 
a  telescoping  "Dural"  tube  fitted  with  a  standard  microphone  hanger. 
When  used  on  the  floor  it  is  either  held  in  the  hand  of  a  boom  man  or 
supported  by  an  auxiliary  stand  similar  to  a  portable  lamp  stand 
which  has  been  fitted  with  a  quiet  roller  to  assist  the  operator  in  sup- 
porting the  boom  and  in  properly  directing  the  microphone.  For 
high  use  the  pole  is  equipped  with  a  ring  placed  near  its  balance  point 
by  which  it  may  be  suspended  by  a  rope  from  a  point  directly  over 
the  set.  By  this  means  the  microphone  may  be '  'flown' '  into  operating 
positions  that  would  be  difficult  to  reach  in  any  other  manner.  The 
use  of  the  fish-pole  type  of  mike  boom  has  proved  most  expedient  for 
use  on  Army  location  pictures. 

Microphone  Preamplifiers. — Feedback  preamplifiers  are  replacing 
earlier  types  to  reduce  noise  and  to  provide  better  quality.  The  wide 
use  of  low  impedance  microphones  allows  the  preamplifier  to  be 
placed  at  almost  any  convenient  location  on  the  set. 

Mixer  Control  Panels. — The  mixer  control  panel  now  in  general  use 
is  mounted  in  a  portable  case  along  with  associate  equipment,  such  as 
volume  indicator,  signal  lights,  telephone  subset,  and  dialog  equal- 
izers. This  case  is  usually  mounted  on  a  portable  wheeled  table  so 
that  the  operating  position  may  be  close  to  the  action  to  be  recorded. 
Lighter  and  smaller  equipment  components  are  needed  for  these  mixer 
panels  to  increase  further  their  ease  of  handling  on  recording  sets. 

Booster  Amplifiers. — Booster  amplifiers  are  usually  mounted  in  the 
mixer  case  and  are  used  when  it  is  necessary  to  send  the  sound  cur- 
rents some  distance  to  the  main  amplifier. 

Main  Amplifiers. — Probably  the  greatest  change  in  amplifiers  in 
the  past  several  years  has  been  the  advent  and  adoption  of  the  com- 
pressor type  or  limiting  type  of  main  amplifier.  By  the  use  of  this 
amplifier,  modulator  overshooting,  with  its  inherent  distortion,  has 
been  eliminated.  Dialog  and  sound  effects  of  excessive  loudness  are 
now  electronically  compressed  to  levels  within  recording  limits. 

As  in  the  case  of  preamplifiers  and  booster  amplifiers,  feedback  is 
being  more  widely  used  to  increase  the  signal-to-noise  ratio  in  the  re- 
cording circuits  and  to  reduce  all  forms  of  distortion. 

Monitoring  Facilities. — The  dynamic  headset  has  largely  replaced 
the  monitor  booths  formerly  employed  on  production  stages.  The 
small  plastic  molded  ear-piece  types  of  headsets  are  also  being  exten- 


294  REPORT  OF  SOUND  COMMITTEE  [J.  S.  M.  P.  E. 

sively  used  because  of  the  improved  coupling  to  the  ear.  Monitor 
rooms  are  used  for  dubbing  and  scoring  work  because  of  the  fixed 
nature  of  these  facilities  and  the  need  for  reverberation  characteristics 
simulating  those  of  a  theater  auditorium. 

Preequalized  Recording  of  Speech  and  Music. — Preequalization  for 
original  recordings,  both  speech  and  music,  is  being  used  by  some 
sound  departments,  and  a  standard  preequalization  characteristic 
is  under  consideration.  No  preequalization  of  the  release  product  is 
being  considered  for  the  duration. 

Recording  Machines. — Sound-recording  machines  have  been  ma- 
terially improved  during  the  past  few  years.  Various  types  of 
sprocketless  recording  drums  of  both  magnetic  and  oil-damped  types 
are  being  employed  to  reduce  flutter,  resulting  in  a  definite  improve- 
ment in  sound  quality.  Improved  fidelity  of  variable-density  re- 
corders has  also  been  attained  by  the  use  of  auxiliary  cylindrical  lenses 
to  reduce  the  effective  valve-image  height  on  the  film.  This  improve- 
ment effectively  eliminates  high-frequency  intermodulation  effects 
and  increases  the  signal-to-noise  range,  since  greater  valve  amplitudes 
may  be  used. 

The  optical  efficiency  of  recording  machines  has  been  improved  by 
the  use  of  coated  lenses.  This  has  been  one  of  the  important  factors 
in  promoting  the  increased  use  of  fine-grain  films  that  require  higher 
light  intensities.  Recorders  are  also  being  equipped  with  photo- 
graphic slating  devices  that  photograph  pertinent  information  for 
each  take  in  the  sound-track  area.  Solenoid  operated  punches  are 
also  being  used  for  marking  the  film  for  preselection  purposes. 

Automatic  starting  and  stopping  circuits  are  being  used  by  some 
studios  to  start,  stop,  and  synchronize  cameras  and  recorders  from  a 
remote  position. 

Films  for  Recording. — The  use  of  fine-grain  films  for  both  sound 
negative  and  prints  and  release  positive  is  now  almost  universal.  The 
reduction  in  film-surface  noise  has  permitted  a  much  higher  quality  of 
reproduction,  particularly  for  critical  dialog  and  musical  sequences. 

Modulators. — There  is  an  increasing  tendency,  for  original  variable- 
density  recording,  toward  the  use  of  200-mil  push-pull  recording.  It 
is  to  be  expected  that  the  use  of  push-pull  recording  for  all  original 
work  will  increase  in  the  future.  The  use  of  Class  B  and  Class  A-B 
variable-area  track  is  also  finding  favor  in  some  of  the  studios,  these 
tracks  being  particularly  desirable  for  super-portable  types  of  record- 


Oct.,  1943]  REPORT  OF  SOUND  COMMITTEE  295 

ing  channels  where  the  elimination  of  the  weight  of  the  noise-reduction 
unit  is  desirable. 

The  use  of  the  super-portable  type  recording  channels  has  proved 
advantageous  in  the  recording  of  Army  training  films  on  location. 

The  resonant  rise  and  high-frequency  transients  of  light- valves  are 
now  being  eliminated  by  the  use  of  electrical  feed-back  networks  that 
also  provide  additional  damping  for  the  valve,  thereby  reducing 
transient  response.  The  damping  of  galvanometers  for  variable-area 
recording  by  the  use  of  tungsten -loaded  rubber  has  also  proved  highly 
effective. 

Re-Recording. — Because  original  sound-tracks  are  much  improved 
by  devices  such  as  push-pull  track,  preequalization,  200-mil  tracks  and 
Class  A-B  and  B  tracks,  it  has  become  necessary  to  re-record  the 
entire  sound-track  for  release  purposes.  Many  unique  equalizers, 
both  automatic  and  manual  in  operation,  are  used  throughout  to 
maintain  a  standard  fidelity. 

Film  Development  Control. — The  intermodulation  meter  for  vari- 
able-density track  and  the  cross-modulation  test  for  variable-area 
track  are  now  being  employed  universally  to  establish  correct  sound- 
film  development  parameters. 

Sensitometric  control  has  been  standardized  throughout  the  indus- 
try by  the  use  of  a  new  electronic  densitometer  of  the  intergrating- 
sphere  type. 

Automatic  developer  replenishment  methods  are  finding  wider 
use  in  the  laboratories  because  of  the  increased  uniformity  in  results 
that  can  be  attained. 

Recording  Stages. — Numerous  improvements  have  been  made  in 
the  design  of  scoring  stages  for  more  effective  recording  of  music. 
Various  types  of  orchestra  shells  have  been  put  into  service  with  a 
definite  improvement  in  sound  quality. 

Motor  Systems. — Improved  test  equipment  has  been  designed  for 
the  rapid  location  of  troubles  in  stage  motor  systems,  particularly 
when  connected  to  camera,  playback,  and  transparency  equipment. 
The  slip-clutch  type  of  synchronous  distributor  is  also  finding  in- 
creased use.  There  is  a  trend  toward  the  standardization  of  1440- 
rpm  stage  drive  motors  for  camera,  playback,  transparency,  and  pro- 
jector equipment.  The  handling  of  transparency  projectors  is  being 
expedited  by  the  use  of  reversible  motors  so  that  all  picture  films  may 
be  rewound  to  any  required  sync  mark  in  a  minimum  of  time  without 
rethreading. 


296 


REPORT  OF  SOUND  COMMITTEE 
COMMITTEE  ON  SOUND 
G.  E.  SAWYER,  Chairman 


J.  O.  AALBBRG 
L.  A.  AICHOLTZ 

G.  FRIEDL,  JR. 
E.  H.  HANSEN 

W.  C.  MILLER 
K.  F.  MORGAN 

M.  C.  BATSEL 

L.  B.  ISAAC 

F.  ROBERTS 

D.  G.  BELL 
D.  BLUMBERG 
F.  E.  CAHILL 

J.  P.  LlVADARY 

J.  A.  MAURER 

R.  McCULLOUGH 

H.  RUBIN 
S.  SOLOW 
W.  V.  WOLFE 

C.  FLANNAGAN 

B.  F.  MILLER 

E.  C.  ZRENNER 

A  NOTE  ON  THE  PROJECTION  LIFE  OF  FILM* 
D.  R.  WHITE  and  C.  DEMOOS  ** 

Summary. — Tests  with  intermittent  sprockets  of  different  diameters  have  shown 
that  the  maximum  projections  which  can  be  attained  depends  greatly  on  a  diameter 
within  the  range  of  0.943  inch  to  0.965  inch  diameters,  about  a  21/%  per  cent  range. 
The  sprocket  pitch  for  best  wear  is  greater  than  the  apparent  match  between  static 
perforation  measurements  and  sprocket  dimensions.  This  is  in  accord  with  the 
view  that  the  elastic  characteristics  of  the  base  are  important  at  this  point  in  the  pro- 
jection cycle.  Tests  with  different  pressures  on  the  film  gate  show  that  this  setting  is 
an  important  factor  affecting  wear  at  the  intermittent  sprocket.  The  way  by  which 
perforations  tear  is  different  under  the  following  two  conditions:  (a)  film  pitch  less 
than  best  match  for  sprocket  pitch,  and  (b}  film  pitch  greater  than  best  match  for 
sprocket  pitch. 

The  conditions  that  are  required  to  attain  a  maximum  film  life 
during  projection  long  have  been  of  interest  in  the  motion  picture 
industry,  but  the  subject  has  rarely  been  of  as  great  importance  as 
it  is  today.  War  conditions  have  emphasized  the  importance  of  all 
steps  leading  to  conservation  of  materials. 

Under  the  most  favorable  conditions  set  up  in  the  tests,  an  average 
projection  life  of  2400  projections  was  reached.  Such  a  large  num- 
ber of  projections  is  not  commonly  attained  under  commercial  con- 
ditions. There  are  many  reasons  for  this:  in  the  first  place,  many 
pictures  do  not  require  such  a  large  number  of  projections*  from  in- 
dividual prints.  Such  a  life  would  account  for  nearly  twq  years  of 
continuous  use,  if  projected  three  times  per  day.  It  is  desirable  to 
cover  the  theaters  with  a  greater  number  of  prints  effecting  shorter 
periods  from  first  to  last  showing  than  would  be  achieved  if  schedules 
were  worked  out  on  the  basis  of  long,  individual  print  life.  In  the 
second  place,  accidents  in  handling  in  projection  and  rewind  rooms 
tend  to  produce  scratches  and  breaks  which  mar  the  film  long  be- 
fore it  would  deteriorate  under  laboratory  conditions. 

The  relationship  between  intermittent  sprocket  diameter,  film 
pitch  and  resultant  wear  was  studied.  For  the  purposes  of  this 
test,  the  unwind  and  rewind  magazines  were  removed  from  a  pro- 

*  Presented  at  the  1943  Spring  Meeting  at  New  York. 

**  E.  I.  Du  Pont  de  Nemours  &  Co.,  Photo  Products  Department,  Parlin,  N.  J. 

297 


298  D.  R.  WHITE  AND  C.  DE  Moos  [J.  S.  M.  P.  E. 

jector  and  auxiliary  idler  rolls  introduced  to  permit  the  continuous 
projection  of  a  short  loop  of  film.  This  arrangement  removed  all 
tension  from  the  pull-down  sprocket  and,  of  course,  changed  condi- 
tions at  the  hold-back  sprocket  since  there  was  now  no  tension 
corresponding  to  the  normal  pull  from  the  wind-up.  The  relief  of 
tensions  at  these  points  reduced  the  system  to  one  in  which  the 
chief  sprocket-hole  wear  was  clearly  traceable  to  the  intermittent 
sprocket. 

It  was  not  possible  to  duplicate  completely  all  the  various  tempera- 
ture and  humidity  conditions  which  might  be  encountered  in  trade 
practice,  but  throughout  these  tests  the  arc  was  used  with  sufficient 
warm-up  time  to  keep  the  gate  and  the  machine  at  a  normal  oper- 
ating temperature.  The  machine  was  in  an  air-conditioned  room, 
and  thus  the  entire  system  was  reasonably  reproducible. 

Previous  experience  had  shown  that  only  a  small  departure  from 
current  commercial  standards  would  be  required  to  produce  marked 
effects  on  film  wear.  Accordingly,  four  sprockets  were  made: 

Sprocket  Root  Dia.  Pitch  at  Median  Line  of  Film 

No.  1  0.943  0.1863 

No.  2  0.948  0.1873 

-No.  3  0.956  0.1889 

No.  4  0.965  0.1907 

With  this  series  of  sprockets  it  was  possible  to  show  the  effect  of 
relative  change  in  film  and  sprocket  pitch.  Results  of  the  first  series 
of  tests  are  shown  in  Table  I. 

TABLE  I 

Projections  with  Sprocket 
Film  Base  Film  Pitch  No.  1         No.  2          No.  3         No.  4 

Nitrate— Sample  1  0.1864  360  1251  1070  774 

Nitrate— Sample  2  0.1868  365  585  1123  468 

Safety— Sample  1  0.1865  90  190  250  162 

Safety— Sample  2  0.1863  144  232  380  374 

The  greatest  number  of  projections  attained,  as  shown  in  italics 
in  Table  I,  shows  strikingly  that  the  longest  life  occurred  where 
sprocket  diameters  were  larger  than  calculated  for  a  perfect  fit,  as 
judged  from  static  measurements  of  film  and  sprocket  dimensions. 
It  was  decided  to  investigate  this  observation  further.  The  pro- 
jector with  which  the  work  was  done  had  been  in  use  for  some  time 
in  wear  studies  and  conditions  of  use  had  been  chosen  to  tear  the 
film  to  pieces  rapidly.  No  changes  were  introduced  when  the  test 


Oct.,  1943]  THE  PROJECTION  LIFE  OF  FILM  299 

was  started,  but  a  recheck  showed  that  the  gate  tension  was  heavier 
than  normal  and  might  have  caused  too  great  a  pull  and  elongation 
of  the  film.  Therefore,  a  second  series  was  run  alter  the  gate  tension 
was  reduced,  with  the  results  shown  in  Table  II. 

TABLE  u 

"Normal"  Gate  Tension 

Projections  with  Sprocket 
Film  Base  Film  Pitch  No.  1          No.  2          No.  3          No.  4 

Nitrate— Sample  1  0.1869  1215  1250  2350  1935 

Nitrate— Sample  2  0.1867  810  1575  2439  2340 

Safety— Sample  1  0.1869  205  545  450  445 

Safety— Sample  2  0.1866  679  1263  1386  1390 

This  table  shows  a  considerable  increase  in  projection  life  over 
the  previous  conditibns,  but,  surprisingly,  it  shows  no  reduction  on 
the  average  in  sprocket  diameter  for  maximum  projections. 

Such  effects  are  difficult  to  explain.  In  the  first  series  the  in- 
dication of  a  maximum  is  so  definite,  at  a  sprocket  pitch  greater 
than  that  of  the  static  film  dimensions,  that  a  general  drop  in  the 
sprocket  pitch  for  maximum  life  was  anticipated  with  a  reduced  gate 
tension.  Table  II  does  not  show  any  such  drop. 

However,  the  favorable  showing  on  projection  life  is  seen  to  be 
definite  regardless  of  an  explanation  of  these  details  of  the  data. 

A  study  of  the  worn  perforations  of  the  film  showed  different, 
typical  tears,  depending  on  the  relative  pitch  of  film  and  sprocket 
during  the  test.  When  the  sprocket  is  small  in  comparison  with 
the  film  pitch,  the  entering  tooth  rubs  the  sprocket-hole,  tending 
to  break  or  tear  it  with  a  push  toward  the  surface  of  the  film  and 
away  from  the  sprocket  itself.  Conversely,  when  the  sprocket  is 
large  in  comparison  with  the  film,  the  film  drags  on  the  tooth  as  it 
withdraws  from  the  film  tending  to  break  or  tear  it  by  a  pull  toward 
the  film  surface  next  to  the  sprocket.  In  the  case  of  the  best  fit  no 
predominant  tear  could  be  found;  in  fact,  many  perforations  had  a 
notch  worn  in  them  the  width  of  a  sprocket  tooth  and  a  few  thou- 
sandths of  an  inch  deep. 

The  results  of  the  tests  emphasize  the  fact  that  small  differences 
of  pitch  can  be  important  in  determining  limits  of  projection  life, 
and  they  suggest  that  much  greater  projection  life  is  possible  than 
is  usually  achieved  under  theater  and  exchange  conditions. 


SOME  CHARACTERISTICS  OF  AMMONIUM  THIOSULFATE 

FIXING  BATHS* 


DONALD  B.  ALNUTT** 


Summary. — A  brief  description  of  the  history  and  nature  of  ammonium  thiosulfate 
is  given.  Several  practical  formulas  employing  this  agent  are  presented  and  their 
advantages  discussed.  Some  of  the  differences  in  characteristics  between  the  am- 
monium thiosulfate  and  sodium  thiosulfate  fixing  baths  are  pointed  out. 

An  explanation  is  offered  to  account  for  the  apparent  discrepancies  in  the  effects  of 
concentration  on  clearing  time  reported  by  previous  investigators.  The  speed  of 
fixation  of  ammonium  thiosulfate  is  shown  to  be  greater  than  sodium  or  lithium  thio- 
sulfates  and  greater  than  mixtures  of  ammonium  chloride  and  sodium  thiosulfate. 

HISTORICAL 

The  author  is  indebted  to  J.  S.  Mertle,1  Technical  Director,  In- 
ternational Photo-Engravers  Union,  for  the  following  brief  account 
of  the  discovery  and  early  application  of  ammonium  thiosulfate  to 
the  photographic  process. 

The  fact  that  ammonium  thiosulfate  will  dissolve  silver  halides 
was  established  long  before  the  development  of  the  photographic 
process  as  it  is  known  today.  Sir  John  F.  W.  Herschel  is  credited 
with  the  discovery  of  the  solvent  action  of  the  thiosulfates  on  silver 
chloride.  His  paper,2  published  in  1819,  mentioned  ammonium 
thiosulfate  as  one  of  the  thiosulfates  which  exerts  solvent  action  on 
silver  chloride.  This  is  probably  the  earliest  mention  of  the  use 
of  ammonium  thiosulfate  for  this  purpose.  The  first  specific  men- 
tion of  the  increased  rate  of  fixing  of  sodium  thiosulfate  in  the  presence 
of  ammonia  or  ammonium  carbonate  was  made  in  1866  by  John 
Spiller,3  who,  two  years  later,4  recommended  it  as  a  fixing  agent  be- 
cause its  greater  solubility  in  water  induced  its  quicker  elimination 
from  plates  and  papers  during  washing  after  fixation.  Practically 
the  same  idea  was  voiced  in  1892  by  Labarre5  who  pointed  out  the 
easy  solubility  of  ammonium  thiosulfate  and  its  more  rapid  action 
as  compared  to  an  equally  concentrated  solution  of  the  sodium 
derivative. 

*  Presented  at  the  1942  Fall  Meeting  at  New  York. 
**  Research  Laboratories,  Mallinckrodt  Chemical  Works,  St.  Louis,  Mo. 
300 


AMMONIUM  THIOSULFATE  FIXING  BATHS  301 

Eduard  Valenta6  in  1895  investigated  the  fixing  action  of  am- 
monium thiosulfate.  He  could  see  no  advantage  in  its  use,  but 
qualified  his  opinion  with  the  statement  that  commercial  samples 
of  the  salt,  at  that  time,  seldom  were  free  from  contamination.  In 
spite  of  Valenta's  verdict,  Eduard  Liesegang7  maintained  his  own 
faith  in  the  superiority  of  the  ammonium  compound.  His  method 
of  preparing  the  salt  involved  the  reaction  of  sodium  thiosulfate 
solution  with  barium  chloride,  followed  by  treatment  of  the  precipi- 
tate with  ammonium  carbonate. 

In  1906,  the  Viennese,  Karl  Seib,  introduced  a  commercial  prepara- 
tion, "Rapid-Fixage,"  which  was  not  a  true  ammonium  thiosulfate, 
but  was  converted  to  this  state  by  admixture  in  water  with  am- 
monium carbonate.  The  same  year  the  German  trust,  Agfa,8 
introduced  a  commercial  fixing  salt  of  ammonium  thiosulfate  con- 
stituency under  the  name  "Agfa-Rapid  Fixing  Salt"  (Agfa-Schnell- 
fixiersalz);  it  was  patented  in  Britain  (No.  25,869)  in  1906. 

Apparently  ammonium  thiosulfate  has  not  heretofore  been  avail- 
able in  this  country  on  a  commercial  scale  in  the  purity  required  for 
photographic  use.  It  is  now  being  offered  as  a  stable  60  per  cent 
solution  and  as  a  stable  anhydrous  crystalline  solid. 

CHEMICAL  NATURE 

Chemically,  ammonium  thiosulfate  is  similar  to  sodium  thiosulfate, 
Na2S2O3  •  5H2O,  except  that  the  sodium  is  replaced  by  the  ammonium 
radical  to  give  the  molecular  formula  (NH4)2S2O3.  Ammonium 
thiosulfate  crystallizes  without  water  of  crystallization  in  colorless, 
glistening  plates  or  sword-shaped  monoclinic  crystals.  Its  molecular 
weight  is  148  compared  with  248  for  sodium  thiosulfate  crystals. 
Thus  six  parts  of  anhydrous  ammonium  thiosulfate  will  take  the 
place  of  ten  parts  of  sodium  thiosulfate  crystals  in  any  given  chemical 
reaction. 

Ammonium  thiosulfate  reacts  chemically  in  much  the  same  way 
as  the  other  soluble  thiosulfates.  It  is  readily  decomposed  by 
heating,  and  its  solutions  sulfurize  readily  when  acidified  in  the 
absence  of  sulfite.  It  has  a  strong  solvent  action  for  silver,  mer- 
curous  and  thallous  chlorides,  bromides,  and  iodides. 

All  of  the  soluble  thiosulfates  appear  to  have  varying  degrees  of 
solvent  action  on  silver  salts.  Although  the  precise  chemical  reac- 
tions involved. in  the  formation  of  soluble  silver  compounds  from 


302  D.  B.  ALNUTT  [J.  S.  M.  P.  E. 

insoluble  silver  halides  are  still  obscure,9'  10  the  reactions  are  gener- 
ally indicated10-  n  as  occurring  in  several  steps  as  follows: 


2AgBr  +  Na2S203  -  >  2NaBr  +  Ag2S2O3  CO 

Ag2S203  +  Na2S203  -  >  Ag2Na2(S203)2  (2) 

Ag2Na2(S203)2  +  Na2S203  —  >  A&Na«(SiO,),  (5) 


As  can  be  seen,  each  succeeding  complex  formed  contains  a  higher 
ratio  of  sodium  to  silver  so  that  the  complex  formed  in  eq.  3  is  the 
highly  soluble  disodium-silver  thiosulfate.  The  solubilities  of  these 
complexes  vary  in  inverse  ratio  to  their  silver  content. 

According  to  Klempt,  Brodkorb,  and  Erlbach,12  the  concentration 
and  density  of  saturated  solutions  of  (NH4)  28203  at  various  tempera- 
tures are  as  follows  : 

TABLE  I 

Per  Cent  by  Weight  and  Density  of  Saturated  Solutions  of  (NH^S^  at  Various 

Temperatures 

Temperature,  °C  Per  Cent  Density 

-10     (14°F)  60.3  1.322 

0     (32°F)  61.6  1.332 

20     (68°F)  64.5  1.342 

40  (104°F)  67.2  1.347 

60  (140°F)  69.4  1.351 

A  60  per  cent  solution  of  ammonium  thiosulfate  is  near  the  satura- 
tion point  and  may  deposit  crystals  in  extremely  cold  weather.  For 
this  reason,  it  is  impractical  to  handle  solutions  of  greater  strength. 

The  relation  between  the  concentration  and  specific  gravity  of 
aqueous  solutions  of  ammonium  thiosulfate  at  25  °G  (77  °F)  is  shown 
in  Fig.  1. 

The  following  table  gives  the  data  on  which  the  curve  in  Fig.  1  is 
based  : 

TABLE  n 

Concentration  and  Specific  Gravity  of  Ammonium  Thiosulfate  Solutions  at 

25°  C  (77  °F) 

Concentration  in  Per  Cent  by  Weight  Specific  Gravity  at  25°C 

4.35  1.0200 

9.23  1.0454 

14.58  1.0743 

19.32  1.1000 

29.07  1.1598 

38.84  1.2076 

53.39  1.2641 


Oct.,  1943]         AMMONIUM  THIOSULFATE  FIXING  BATHS 


303 


CHARACTERISTICS 

The  time  of  clearing,  and  consequently  the  time  of  fixation  of  an 
ammonium  thiosulfate  fixing  bath,  is  approximately  one-fourth  that 
of  the  common  sodium  thiosulfate  fixing  baths. 

Fixing  baths  made  with  ammonium  thiosulfate  appear  to  retain 
their  hardening  action  over  a  wider  range  of  pH  than  the  sodium 
thiosulfate  baths.  The  commonly  used  hypo-fixing  baths  appear 
to  lose  their  hardening  action  when  the  £H  has  been  raised  to  be- 
tween 5.5  and  5.8,  although  their  fixing  power  still  may  be  good; 
but,  an  ammonium  thiosulfate  aluminum  salt  bath  will  retain  satis- 
factory hardening  action  up  to  a  pH  of  6.5  to  7.  This  characteristic 


1.300 


5   1.200 


ac 
o 

-    1. 100 
It, 


1.000 


10  20  30  40  50 

PERCENT    BY   WEIGHT     (NH4)2S203 

FIG.  1. 


is  a  definite  advantage,  since  it  means  that  an  ammonium  thio- 
sulfate fixing  bath  will  harden  satisfactorily  more  film  than  will  a 
similar  sodium  thiosulfate  bath. 

Concentrated  fixing  baths  requiring  only  dilution  for  use  can  be 
readily  prepared  with  ammonium  thiosulfate.  This  is  due  not 
only  to  the  slightly  greater  solubility  of  ammonium  thiosulfate,  but 
to  the  fact  that  equal  or  greater  efficiency  can  be  obtained  from  the 
lower  concentration  of  ammonium  thiosulfate.  Thus,  formula 
ATF-1,  which  follows,  can  be  prepared  as  a  concentrated  solution 
in  only  25  per  cent  of  its  final  volume,  whereas  a  comparable  hypo 
bath  would  require  40  per  cent  of  its  final  volume  for  a  concentrated 


304  D.  B.  ALNUTT  [j.  s.  M.  P.  E. 

solution  in  which  all  the  ingredients  would  be  maintained  in  com- 
plete solution. 

Little  difference  is  observed  in  the  clarity  of  films  just  after  fixa- 
tion in  either  ammonium  or  sodium  thiosulfate  fixing  baths.  How- 
ever, films  fixed  in  ammonium  thiosulfate  solutions  of  greater  than 
normal  concentration  were  clearer  just  after  fixation  than  those 
fixed  in  similar  concentrations  of  sodium  thiosulfate.  This  is  es- 
pecially true  of  x-ray  films. 

It  is  generally  known  that  prolonged  treatment  of  a  photographic 
image  in  an  acid-hardening  fixing  bath  will  reduce  the  density  of  the 
silver  deposit.  Experiments  designed  to  compare  the  reducing 
action  of  ammonium  thiosulfate  and  sodium  thiosulfate  fixing  baths, 
both  fresh  and  used,  indicate  that  the  reducing  action  of  ammonium 
thiosulfate  is  no  greater  than  that  of  sodium  thiosulfate,  except  for 
papers  and  process  film. 

The  recently  published  F-7  formula  of  Crabtree  et  a/.,13  using 
ammonium  chloride  to  give  greater  fixing  speed,  was  compared  with 
ammonium  thiosulfate  fixing  baths,  both  as  to  speed  and  hardening 
properties.  It  was  found  that  ammonium  chloride  additions  to 
regular  sodium  thiosulfate  fixing  baths  increased  their  speed  con- 
siderably, but  that  these  baths  were  still  slower  in  their  fixing  action 
than  straight  ammonium  thiosulfate  baths.  Furthermore,  am- 
monium chloride  seems  to  decrease  the  hardening  action  of  such 
baths. 

It  was  thought  that  the  greater  solubility  of  ammonium  thio- 
sulfate might  increase  the  ease  of  washing  it  out  of  emulsions.  How- 
ever, washing  experiments  indicate  that  this  agent  is  eliminated  at 
about  the  same  rate  as  sodium  thiosulfate. 

FORMULATION 

The  modern  acid-hardening  fixing  bath  is  expected  to  perform 
other  functions  besides  transforming  silver  halides  into  soluble  salts. 
Some  of  these  other  functions  are:  hardening  the  emulsion,  stopping 
development,  and  preventing  stains.  In  order  to  accomplish  these 
results  satisfactorily,  an  acid-hardening  fixing  bath  should  have 
certain  qualities.  Crabtree  and  Hartt14  enumerate  six  important 
requirements  for  a  satisfactory  acid-hardening  fixing  bath  which, 
briefly  summarized,  are  as  follows: 

(1)  It  should  fix  with  sufficient  rapidity 

(2)  It  should  not  sulfurize. 


Oct.,  1943]         AMMONIUM  THIOSULFATE  FIXING  BATHS  305 

(5)  It  should  not  form  a  sludge. 

(4}  It  should  not  cause  blisters  on  film . 

(5)  It  should  produce  sufficient  hardening. 

(6)  It  should  have  a  satisfactory  service  life. 

In  devising  formulas  using  ammonium  thiosulfate,  our  aim  was 
to  produce  fixing  baths  which  would  retain  all  of  the  speed  of  fixing 
possessed  by  simple  solutions  of  the  agent;  which  would  have  no 
deleterious  effect  on  the  photographic  emulsion;  and  also  would 
have  sufficient  hardening  action.  Other  requirements,  such  as 
stability  of  the  solutions,  service  life  of  the  bath,  etc.,  were  con- 
sidered of  secondary  importance. 

Baths  were  first  formulated  using  ammonium  compounds  through- 
out; that  is,  ammonium  tliiosulfate,  ammonium  sulfite,  and  am- 
monium alum.  Such  baths  were  found  to  have  no  advantages  over 
baths  made  with  ammonium  thiosulfate,  sodium  sulfite,  and  potas- 
sium alum.  In  fact,  the  speed  of  fixation  was  found  to  be  influenced 
almost  entirely  by  the  concentration  of  the  ammonium  thiosulfate 
used  in  the  formulation  of  the  bath.  For  this  reason  the  formulas 
devised  and  tested  were  based  largely  on  known  satisfactory  formulas 
by  substituting  ammonium  thiosulfate  for  sodium  thiosulfate  in 
varying  proportions. 

Ammonium  Thiosulfate  General  Purpose  Acid-Hardening  Fixing 
Bath. — This  bath  contains  approximately  150  grams  of  anhydrous 
ammonium  thiosulfate  per  liter.  At  the  time  this  concentration 
was  chosen,  it  was  believed  that  this  strength  produced  the  most 
rapid  fixing  action,  although  later  it  was  learned  that  the  speed  of 
fixation  increased  as  the  concentration  was  increased  up  to  a  satu- 
rated solution.  The  amount  of  sodium  sulfite  was  chosen  to  conform, 
in  general,  to  concentrations  used  in  known  satisfactory  fixing 
baths.  The  amount  of  boric  acid  was  chosen  for  the  same  reason, 
since  baths  using  this  concentration  are  known  to  inhibit  satis- 
factorily the  precipitation  of  an  aluminum  sulfite  sludge. 

In  sodium  thiosulfate  baths,  aluminum  chloride  is  said  to  have 
several  advantages  over  alum,15  the  most  important  of  which  is  its 
increase  in  the  sludging  and  sulfurization  life  of  the  bath.  It  was 
found  experimentally  that  aluminum  chloride  was  a  satisfactory 
hardening  agent  in  ammonium  thiosulfate  baths.  The  amount  of 
acetic  acid  was  determined  by  empirical  methods  so  that  the  pH 
produced  was  in  the  known  critical  range  for  the  proper  functioning 
of  the  aluminum  as  the  hardening  agent.  The  selection  of  aluminum 


306  D.  B.  ALNUTT  [J.  S.  M.  P.  E. 

chloride  as  the  hardening  agent  made  it  possible  to  use  this  formula 
as  a  concentrated  ready-to-use,  two-solution  fixing  bath.  The 
A  TF-1  formula  is  given  both  in  the  ready-to-use  form  and  in  a  con- 
centrated solution  form  suitable  for  liquid  packaging. 

ATF-l 

Ammonium  Thiosulfate  General  Purpose  Acid-Hardening  Fixing  Bath 

One  Liter 
Ingredients  Ready-to-Use        Concentrated 

Water  700  cc 

Ammonium  thiosulfate,  60  per  cent  solution  185  cc  185  cc 

Sodium  sulfite,  anhydrous  12  gm  12  gm 

Acetic  acid,  glacial  9  cc  9  cc 

Boric  acid  7 . 5  gm  7 . 5  gm 

Water,  enough  to  make  250  cc 

Aluminum  chloride  hexahydrate  12. 5  gm  12. 5  gm 

Water,  enough  to  make  1000  cc  25  cc 

Dissolve  the  chemicals  in  the  order  given.  Add  the  acetic  acid  slowly 
while  stirring.  Dissolve  the  boric  acid  in  a  small  amount  of  hot  water 
before  adding  it.  When  making  the  concentrated  formula,  keep  the 
aluminum  chloride  solution  separate  until  ready  to  make  up  the  bath. 
To  prepare  a  ready-to-use  fixing  bath,  the  concentrated  solution  should 
be  diluted  with  750  cc  of  water  and  the  aluminum  chloride  solution  added 
slowly  while  stirring. 

The  A  TF-1  formula  has  been  found  to  have  good  service  life,  ex- 
cellent hardening  action,  and  rapid  clearing  action.  When  made  up 
in  concentrated  form,  the  solutions  are  remarkably  stable.  Because 
of  this  latter  property,  this  bath  is  well  suited  for  x-ray  work. 

Ammonium  Thiosulfate-Chrome  Alum  Acid-Hardening  Fixing 
Bath. — Formula  A  TF-2  was  developed  to  produce  a  fixing  bath  whose 
hardening  action  could  keep  pace  with  its  fixing  action.  It  is  well 

ATF-2 

Ammonium  Thiosulfate-Chrome  Alum  Acid-Hardening  Fixing  Bath 

Ingredients  One  Liter 

Water  700  cc 

Ammonium  thiosulfate,  60  per  cent  solution  185  cc 

Sodium  sulfite,  anhydrous  15  gm 

Sulfuric  acid,  5  per  cent  80  cc 

Potassium  chrome  alum  15  gm 

Water,  enough  to  make  1000  cc 

Dissolve  the  chemicals  in  the  order  given.  To  make  sulfuric  acid 
5  per  cent,  add  5  cc  of  C.  P.  acid  to  95  cc  of  cold  water  slowly  with 
rapid  agitation. 


Oct.,  1943]         AMMONIUM  THIOSULFATE  FIXING  BATHS  307 

known  that  chrome  alum  gives  not  only  extreme  hardening  of  gelatin 
emulsions,  but  that  this  action  is  relatively  rapid  when  it  is  used  in  a 
bath  whose  acidity  is  properly  adjusted. 

This  bath  produced  satisfactory  hardening  within  the  time  neces- 
sary for  it  to  clear  most  types  of  emulsions.  In  common  with  most 
chrome  alum  acid-hardening  fixing  baths,  the  service  life  of  this 
bath  is  short  and  it  has  poor  keeping  qualities. 

Ammonium  Thiosulf ate- Chrome  Alum  Acid-Hardening  Fixing 
Bath  (Suitable  for  Dry  Packaging) . — Since  the  rapid  hardening,  rapid 
clearing  type  of  fixing  bath  would  be  useful  largely  in  military  opera- 
tions, race  tracks,  news  work,  etc.,  it  was  considered  desirable  to 
create  a  formula  of  this  type  that  could  be  packaged  as  dry  chemicals 
to  facilitate  the  distribution  of  such  a  fixing  bath.  Formula  A  TF-3, 
which  follows,  takes  advantage  of  the  strong  acidic  properties  of  the 
stable,  solid  sulfamic  acid16'17  to  produce  a  fixing  bath  having  essen- 
tially the  same  properties  as  ATF-2.  It  was  also  found  necessary 
to  use  a  slightly  dehydrated  form  of  potassium  chrome  alum,  dried 
to  about  85  per  cent  of  its  original  weight,  to  give  a  mixture  of  acidic 
ingredients  that  would  not  cake  in  the  package.  The  amount  of 
ammonium  thiosulfate  was  also  increased  in  this  bath  to  take  ad- 
vantage of  the  slight  but  important  decrease  in  clearing  time  which 
this  concentration  would  produce. 

ATF-3 

Ammonium  Thiosulf  ate- Chrome  Alum  Acid-Hardening  Fixing  Bath  (Suitable  for 

Dry  Packaging) 

Ingredients  One  Liter 

Ammonium  thiosulfate,  anhydrous  200  gm 

Sodium  sulfite,  anhydrous  15  gm 

Potassium  chrome  alum  (dried)  13  gm 

Sulfamic  acid  9  gm 

(To  make  potassium  chrome  alum  (dried),  dry  the  regular 
chrome  alum  slowly  to  drive  off  about  15  per  cent  of  its  original 
weight.) 

Mix  the  ammonium  thiosulfate  and  the  sodium  sulfite  and 
package  in  a  large  container.  Mix  the  alum  and  the  acid  and 
package  in  a  small  separate  container.  For  use,  dissolve  the 
ingredients  of  the  large  container  in  approximately  700  cc  of 
water.  Dissolve  the  acidic  ingredients  from  the  smaller  con- 
tainer in  about  100  cc  of  water  and  add  this  solution  to  the 
former  slowly  while  stirring.  Make  up  the  final  volume  to 
1000  cc. 


308  D.  B.  ALNUTT  [J.  S.  M.  P.  E. 

Fixing  baths  made  from  powders  compounded  according  to  the 
ATF-3  formula  behave  very  similarly  to  the  ATF-2  fixing  bath. 
The  powders  themselves  have  proved  to  be  reasonably  stable  over  a 
storage  period  of  four  months  except  that  the  solid  ammonium  thio- 
sulfate  has  a  tendency  to  cake  slightly.  This  tendency  has  not  been 
found  to  be  detrimental  to  the  use  of  this  type  of  package. 

Ammonium  Thiosulfate  General  Purpose  Acid-Hardening  Fixing 
Bath  (Suitable  for  Dry  Packaging}. — A  formula  consisting  entirely 
of  solid  ingredients  that  would  give  a  bath  similar  in  properties  to 
the  A  TF-1  fixing  bath  was  also  developed.  In  this  project,  we  were 
guided  by  the  recent  work  of  Woosley  and  Pankhurst18  who  made 
use  of  the  combination  of  sodium  acetate  and  sodium  bisulfate  to 
produce  the  necessary  acidity  in  their  fixing  baths.  These  authors 
used  equal  weights  of  acetate  and  bisulfate.  We  found  that  a  ratio 
of  bisulfate  to  anhydrous  acetate  of  three  to  two  gave  a  bath  of 
proper  £H  for  satisfactory  functioning  of  the  hardening  agent. 

ATF-4 

Ammonium  Thiosulfate  General  Purpose  Acid-Hardening  Fixing  Bath  (Suitable  for 

Dry  Packaging) 
Ingredients  One  Liter 

Ammonium  thiosulfate,  anhydrous  150  gm 

Sodium  sulfite,  anhydrous  15  gm 

Sodium  acetate,  anhydrous  21  gm 

Boric  acid  10  gm 

Sodium  bisulfate  31  gm 

Potassium  alum  15  gm 

Package  the  ammonium  thiosulfate  and  sodium  sulfite  in  a 
large  container.  Make  a  separate  moisture-proof  packet  of  the 
sodium  acetate  and  place  it  in  the  large  package.  Mix  the 
boric  acid,  sodium  bisulfate,  and  potassium  alum  and  package 
in  a  small  container.  To  make  up  the  solution,  dissolve  the 
contents  of  the  large  package  in  about  700  cc  of  water  and  add 
the  sodium  acetate  from  the  small  packet.  Dissolve  the  con- 
tents of  the  smaller  package  in  about  200  cc  of  warm  water 
Add  the  second  solution  to  the  first  slowly  while  stirring. 

Exhaustion  tests  on  this  bath  indicate  that  it  has  good  service  life, 
produces  satisfactory  hardening,  and  has  satisfactory  capacity  for 
carried-over  developer.  Keeping  tests  have  not  been  completed 
on  the  dry  packaged  chemicals,  but  after  two  months  they  appear 
to  be  stable. 


Oct.,  1943]         AMMONIUM  THIOSULFATE  FIXING  BATHS  309 

Ammonium  Thiosulfate  General  Purpose  Acid-Hardening  Fixing 
Bath. — Since  aluminum  chloride  hexahydrate  is  not  a  common 
photographic  chemical,  a  fixing  bath  having  characteristics  similar 
to  the  A  TF-1  was  developed,  using  the  regular  photo  grade  of  potas- 
sium alum.  It  was  also  found  that  by  increasing  the  amount  of  the 
ammonium  thiosulfate  to  200  grams  per  liter  a  considerable  exten- 
sion of  the  service  life  of  the  bath  could  be  obtained.  Furthermore, 
the  solid  ammonium  thiosulfate  was  designated  in  this  foimula, 
since  this  type  of  material  is  more  adaptable  to  commercial  handling. 
The  A  TF-5  formula,  which  follows,  incorporates  these  modifications. 

ATF-5 

Ammonium  Thiosulfate  General  Purpose  Acid-Hardening  Fixing  Bath 

Ingredients  One  Liter 

Water  700  cc 

Ammonium  thiosulfate,  anhydrous  200  gm 

Sodium  sulfite  15  gm 

Acetic  acid,  28  per  cent  55  cc 

Boric  acid  7.5gm 

Potassium  alum  15  gm 

Water,  enough  to  make  1000  cc 

Dissolve  the  chemicals  in  the  order  given.  Dissolve  the  boric 
acid  in  a  small  amount  of  hot  water  and  add  it  to  the  bulk  of  the 
solution. 

This  bath  was  found  to  have  an  exceptionally  long  service  life, 
and  it  produced  satisfactory  hardening  over  a  long  period  of  time. 
All  of  its  ingredients,  except  the  ammonium  thiosulfate,  are  regularly 
available  in  any  photographic  laboratory. 

A  more  complete  description  of  the  properties  of  these  formulas 
will  be  given  in  the  experimental  section  that  follows.  It  is  believed 
that  ammonium  thiosulfate  can  be  used  to  advantage  not  only  in 
the  general  type  of  fixing  bath,  but  also  in  formulas  designed  for 
special  types  of  work,  such  as  non-hardening  fixing  baths  and  re- 
plenishers  for  acid-hardening  baths. 

EXPERIMENTAL 

Rate  of  Fixing. — The  chief  advantage  of  the  ammonium  thio- 
sulfate fixing  bath  is  the  rapidity  with  which  it  fixes  photographic 
emulsions.  In  order  to  study  the  rate  of  fixation,  a  method  of  deter- 
mining "clearing  time"  was  first  adopted.  It  is  well  known  that  the 


310  D.  B.  ALNUTT  [J.  S.  M.  p.  E. 

clearing  time  is  the  time  necessary  for  the  turbidity  of  the  silver  salt 
in  the  emulsion  to  disappear.  Evidence  has  been  produced  to  in- 
dicate that  the  fixing  time  is  synonymous  with  the  clearing  time.19-  20 
However,  Warwick21  showed  that  fixation  should  be  continued  for 
twice  the  clearing  time  to  be  sure  of  removing  all  the  unreduced 
silver  salts.  It  is  a  generally  accepted  safety  measure  to  fix  all 
photographic  emulsions  for  twice  as  long  as  it  takes  for  them  to 
clear  if  permanence  is  desired. 

Numerous  experimenters  have  used  various  means  of  measuring 
the  clearing  time  of  photographic  emulsions.  An  adaptation  of  the 
method  of  C.  Welborne  Piper22  seemed  to  give  the  most  reproducible 
results  and  it  was  used  in  these  experiments.  With  the  hope  that 
some  day  some  such  method  may  be  standardized,  a  complete  de- 
scription of  the  method  used  in  these  experiments  is  given : 

The  fixing  solution  to  be  tested  was  placed  in  a  shallow  glass  tray.  A  sheet  of 
matte-finish,  black  paper  of  sufficient  size  to  cover  the  bottom  of  the  tray  was 
immersed  in  the  fixing  solution  to  provide  a  black  background  (paper  usually 
packaged  between  sheets  of  cut  film  was  found  to  be  satisfactory  for  this  purpose) . 
A  streak  or  puddle  of  the  fixing  solution  to  be  tested  was  placed  on  the  center  of 
the  strip  of  film  to  be  tested,  using  a  glass  rod,  and  the  streak  was  allowed  to  re- 
main on  the  film  for  approximately  one-fourth  of  the  expected  clearing  time. 

When  wet  film  was  used,  it  was  difficult  to  prevent  the  fixing  solution  from 
running  over  the  film,  so  an  alternate  method  was  used;  such  as  immersing  one 
end  of  the  strip  or,  better  still,  bending  the  strip  in  the  form  of  a  horseshoe  and 
immersing  the  center  portion  of  the  strip  in  the  bath  for  approximately  one-fourth 
of  the  expected  clearing  time.  Then,  the  entire  strip  of  film  was  plunged  into  the 
fixing  solution  and  a  stop  watch  was  started  simultaneously.  The  strip  of  film 
was  vigorously  shaken  when  first  immersed  and  was  given  two  or  three  shakes  at 
ten-second  intervals  thereafter. 

The  best  method  of  observing  the  disappearance  of  the  turbidity  of  the  emulsion 
was  to  view  the  strip  of  film  at  a  low  angle  using  illumination  placed  directly  above 
the  tray.  It  also  helped  to  have  a  dark-colored  background  on  the  opposite  side 
of  the  dish  from  which  the  observation  was  made. 

End  of  Clearing  Time 

(a)  For  combinations  of  films  and  solutions  that  produced  completely  trans- 
parent emulsions,  the  clearing  time  was  taken  as  that  point  at  which  the  last 
trace  of  turbidity  disappeared.     If  traces  of  turbidity,  which  were  patently  caused 
by  finger  marks  or  contamination,  remained  after  the  clear  portion  of  the  film 
had  become  largely  transparent,  they  were  disregarded. 

(b)  For  combinations  of  films  and  solutions  that  failed  to  give  completely 
transparent  emulsions,  the  clearing  time  was  taken  as  that  point  at  which  the 
streak  or  blotch  produced  by  the  preliminary  treatment  with  the  solution  became 
indistinguishable  from  the  remainder  of  the  emulsion. 


Oct.,  1943]        AMMONIUM  THIOSULFATE  FIXING  BATHS 


311 


The  concentration  of  the  fixing  bath,  the  type  of  emulsion  used, 
the  temperature  of  the  fixing  bath,  and,  to  a  slight  extent,  the  in- 
gredients used  in  the  acid-hardening  solution,  all  influence  the  rate  of 
clearing.  The  concentration  of  the  fixing  bath  has  the  largest 
single  effect  on  the  clearing  time  and  will  be  considered  first. 

Conflicting  views  on  the  relationship  between  clearing  time  and 
concentration  of  sodium  thiosulfate  have  been  reported.  C.  Wei- 
borne  Piper22  in  1913  concluded  that  there  was  an  optimum  con- 
centration of  sodium  thiosulfate  at  which  the  clearing  time  was  a 
minimum.  Above  or  below  this  concentration  the  clearing  time 
increased.  When  the  data  were  plotted  with  the  clearing  time  along 


o 

5      4 

2     3 

d     2 
i 


50    100          200          300         400          500         600 
CONCENTRATION    IN    GRAMS   PER    LITER 

FIG.  2. 


700 


the  vertical  axis  and  the  concentration  along  the  horizontal,  a  gener- 
ally broad  based,  ^/-shaped  curve  resulted.  The  bottom  of  the  U 
was  the  point  of  most  rapid  clearing,  and  it  occurred  at  a  concentra- 
tion of  about  40  per  cent  sodium  thiosulfate  at  20  °C  (68  °F).  Crab- 
tree  and  Hartt14  reached  the  same  general  conclusion  in  1929.  In 
striking  contrast  to  these  findings,  Hanson23  recently  showed  that  the 
clearing  time  progressively  decreased  with  increases  in  the  concen- 
tration of  sodium  thiosulfate.  He  found  no  optimum  concentration 
at  which  clearing  time  was  at  a  minimum  and  offered  no  explanation 
of  the  apparent  contradiction  between  his  observations  and  those 
of  the  earlier  workers. 


312 


D.  B.  ALNUTT 


[J.  S.  M.  P.  E. 


We  have  now  found  that  in  the  case  of  ammonium  thiosulfate 
either  type  of  clearing  time  curve  can  be  obtained,  depending  upon 
whether  the  measurement  is  made  on  dry  or  wet  film.  Based  on 
our  observations,  our  conclusion  is  that  Piper,  and  Crabtree  and 
Hartt  must  have  measured  clearing  time  on  dry  film  while  Hanson 
must  have  used  wet  film.  When  a  dry  emulsion  is  immersed  in  a 
fixing  solution,  the  solution  must  wet  and  diffuse  into  the  emulsion 
before  chemical  reaction  can  take  place.  Dry  emulsions  placed 
directly  in  40  per  cent  to  50  per  cent  sodium  thiosulfate  solutions  do 
not  clear  in  an  hour  or  more  at  room  temperatures.  Wet  emulsions 
similarly  treated  clear  readily.  That  the  more  highly  concentrated 


14 
13 

ul    12 
r>    H 

-     10 

~      8 


50     100          200  300          400          500          600          700 

CONCENTRATION    IN    GRAMS    PER    LITER 

FIG.  3. 

solutions  do  not  diffuse  into  the  dry  emulsion  as  rapidly  as  the  more 
dilute  solutions  seems  entirely  reasonable. 

In  our  work  we  measured  the  clearing  time  of  wet  film,  since  this 
gives  values  of  more  practical  photographic  significance. 

Fig.  2  shows  the  clearing  times  of  Super-JOT  film  at  various  con- 
centrations of  both  sodium  and  ammonium  thiosulfates.  The  film 
was  soaked  in  distilled  water  for  five  minutes  before  each  determina- 
tion was  made.  The  main  curves  show  the  clearing  times  of  the  two 
agents  at  25  °C  (77  °F).  Supplementary  curves  in  broken  lines  show 
the  clearing  times  at  20  °C  (68  °F)  and  15°C  (59  °F).  Not  only  is  the 
time  of  clearing  shorter  at  the  higher  temperatures,  but  it  will  be 
noted  that  the  retarding  action  of  high  concentrations  is  practically 


Oct.,  1943]         AMMONIUM  THIOSULFATE  FIXING  BATHS  313 

absent  at  25  °C  (77  °F).  The  wide  difference  in  speed  between  the 
action  of  the  sodium  and  the  ammonium  thiosulfate  is  apparent. 
The  time  of  clearing  for  the  ammonium  thiosulfate  becomes  rapidly 
less  as  the  concentration  is  increased  up  to  about  20  per  cent.  There- 
after, the  increased  speed  is  not  commensurate  with  the  extra  quanti- 
ties of  the  agent  used.  It  is  apparent  that  a  solution  of  ammonium 
thiosulfate  containing  200  grams  per  liter  is  as  rapid  in  its  action  as 
that  of  a  sodium  thiosulfate  solution  containing  700  grams  per  liter. 

Schramm24  has  suggested  that  lithium  thiosulfate  might  give  even 
more  rapid  clearing  action  than  ammonium  thiosulfate.  Clearing 
times  were  run  on  solutions  of  different  strengths  of  lithium  thio- 
sulfate, in  the  same  manner  as  those  illustrated  in  Fig.  2.  Fig.  3 
shows  the  clearing  times  at  20  °C  (68  °F)  of  Super-JO"  film  at  various 
concentrations  for  all  three  thiosulfates.  As  can  be  seen,  the  clear- 
ing times  of  lithium  thiosulfate  fall  between  those  of  the  sodium  and 
the  ammonium  thiosulfates.  It  is  interesting  to  note  that  the  re- 
tarding effect  of  higher  concentrations  of  lithium  thiosulfate  on  the 
clearing  times  is  much  more  pronounced  than  it  is  with  ammonium 
thiosulfate. 

Experimental  determinations  of  clearing  times  at  widely  variant 
temperatures  indicate  that  temperature  is  also  an  important  factor 
affecting  the  clearing  time.  An  idea  of  this  effect  may  be  had  from 
the  fact  that  a  15  per  cent  solution  of  ammonium  thiosulfate  re- 
quires two  and  one-quarter  minutes  to  clear  Super-X^T  film  at  10°C 
(50  °F),  but  at  60  °C  (140°F)  this  same  solution  clears  the  emulsion 
in  fifteen  seconds. 

Various  types  of  emulsions  require  different  fixing  times,  as  in- 
dicated by  Table  III  below.  The  clearing  times  are  given  in  seconds 
for  a  solution  of  ammonium  thiosulfate  containing  148  grams  per 
1000  cc,  as  compared  to  a  solution  of  sodium  thiosulfate  containing 
248  grams  of  the  crystalline  solid  per  1000  cc. 

TABLE  ni 
Clearing  Time  in  Seconds  of  Various  Emulsions  at  20° C  (68° F) 

Type  of  Film  (NH4)2S2O»  NajSzO.- 

Process  13  21 

X-ray  35  96 

Fast  Fine-Grain  50  215 

Super-Fast  Panchromatic  52  210 

Standard  Panchromatic  58  238 

Orthochromatic  60  240 


314  D.  B.  ALNUTT  [j.S.  M.  P.E. 

These  two  concentrations  of  the  thiosulfates  are  chemically 
equivalent.  It  will  be  noted  that  the  ammonium  thiosulfate  clears 
the  film  in  from  one-half  to  one-quarter  the  time  required  by  the 
sodium  thiosulfate  solution. 

Another  factor,  which  might  possibly  affect  the  clearing  time  of 
emulsions,  is  the  pre-treatment  of  the  emulsion  before  it  reaches  the 
fixing  bath.  In  nearly  every  case  this  pre-treatment  will  include 
development,  which  means  exposure  for  a  period  of  several  minutes 
to  a  solution  of  strong  alkalinity  and  a  rinse  in  a  short  stop  bath  with 
or  without  a  hardener.  Experiments  of  Sheppard  and  Mees25  in- 
dicated that  formalin  hardening  had  no  effect  on  the  rate  of  fixation 
of  photographic  film.  Experiments  by  Crabtree  and  Hartt14  indi- 
cated that  excessive  quantities  of  the  hardener  constituents  of  a 
stop  bath  absorbed  into  the  emulsion  would  retard  fixation.  For 
all  practical  purposes,  when  using  normal  hardening  baths,  the 
hardener  did  not  materially  affect  the  time  of  fixation.  One  or  two 
simple  tests  confirmed  these  statements  in  our  own  experiments. 

Extensive  experiments  showed  that  the  amount  of  absorbed  water 
contained  in  the  emulsion  had  a  large  effect  on  the  clearing  time. 
This  was  especially  true  of  concentrations  of  thiosulfate  higher  than 
those  ordinarily  used.  It  did  not  appear  to  make  any  difference 
whether  the  film  was  first  soaked  in  a  developer,  a  sodium  carbonate 
solution,  or  plain  water,  as  long  as  the  emulsion  had  been  permitted 
to  absorb  sufficient  water.  Experiments  on  the  length  of  time 
necessary  for  the  Super- JOT  emulsion  to  absorb  sufficient  water  for 
its  clearing  time  to  reach  a  minimum  in  any  particular  concentration 
of  thiosulfate,  showed  that  at  20  °C  (68  °F)  the  time  was  approxi- 
mately three  minutes.  Therefore,  in  all  clearing  time  tests,  the 
standard  preliminary  treatment  was  to  soak  the  emulsion  to  be 
tested  in  distilled  water  at  20°C  (68°F)  for  at  least  five  minutes. 

Clarity  of  Fixed  Emulsions. — It  has  been  claimed  by  Dawson26 
that  ammonium  thiosulfate  fixing  baths  produce  a  completely  trans- 
parent image  as  soon  as  the  film  is  cleared,  whereas  sodium  thio- 
sulfate fixing  baths  ordinarily  leave  a  haze  in  the  image  until  the  film 
has  been  completely  washed.  We  found  that  #-ray  films  fixed  in 
ammonium  thiosulfate  solutions  containing  200  grams  per  liter  were 
clearer  than  those  fixed  in  sodium  thiosulfate  solutions  of  this  con- 
centration. Below  this  concentration  the  differences  in  clarity  were 
not  significant.  At  concentrations  greater  than  200  grams  per  liter, 
the  difference  in  clarity  was  more  pronounced.  When  this  experi- 


Oct.,  1943]        AMMONIUM  THIOSULFATE  FIXING  BATHS  315 

ment  was  repeated,  using  Super-XJT  film,  little  or  no  difference  in 
clarity  could  be  noticed  between  the  ammonium  and  sodium  thio- 
sulfate  solutions  until  a  concentration  of  260  grams  per  liter  was 
reached.  Dawson's  claim  was  substantiated  in  the  case  of  x-ray 
films,  but  a  comparable  difference  does  not  seem  to  exist  with  Super- 
XX  film. 

Reducing  Action. — The  fact  that  fresh  fixing  baths  have  a  definite 
reducing  action  on  the  silver  image  of  a  photographic  emulsion  has 
been  known  for  some  time.  Russell  and  Crabtree27  in  1932  studied 
the  reducing  action  of  fresh  fixing  baths  on  the  silver  image  of  a 
photographic  emulsion.  They  concluded  that  the  amount  of  re- 
duction produced  by  a  given  fixing  bath  was  directly  proportional 
to  its  acidity.  Therefore,  when  using  fresh  chrome  alum  baths 
having  high  acidity,  the  amount  of  reduction  became  important. 
However,  in  ordinary  work,  except  with  very  fresh  potassium  alum 
baths,  this  reducing  action  was  insignificant.  Dawson26  has  pointed 
out  that  the  reducing  action  of  ammonium  thiosulfate  fixing  baths 
at  equal  />H  values  was  definitely  greater  than  those  of  sodium 
thiosulfate  fixing  baths  on  x-ray  film.  It  also  has  been  reported 
by  J.  S.  Mertle1  that  experiments  with  process  plates  used  in  lithog- 
raphy have  definitely  showed  that  the  opacity  of  the  dots  can  be 
lessened  materially  by  prolonged  treatment  in  the  A  TF-1  fixing  bath. 
Therefore,  it  is  recommended  that  process  films  or  plates  should  be 
allowed  to  remain  in  ammonium  thiosulfate  fixing  baths  not  longer 
than  double  their  clearing  time. 

Experiments  with  photographic  papers  have  shown  that  the 
fresh  ammonium  thiosulfate  fixing  baths  can  have  a  decided  re- 
ducing action  on  the  images.  Ammonium  thiosulfate  fixing  bath 
formulas,  containing  150  grams  per  liter,  appeared  to  give  no  notice- 
able reduction  in  a  10-minute  fixing  period.  However,  formulas 
using  200  grams  per  liter,  such  as  ATF-4  andATF-5,  have  a  marked 
effect  within  eight  minutes.  Therefore,  when  fixing  baths  ATF-4 
and  5  are  used  for  photographic  paper,  it  is  recommended  that  the 
prints  should  not  be  allowed  to  remain  in  the  bath  longer  than  four 
minutes.  The  high  acidity  chrome  alum  formulas  should  not  be 
used  for  photographic  paper. 

Hardening  Properties. — The  most  important  property  of  any 
fixing  bath,  besides  its  ability  to  fix  emulsions  properly  without 
deleterious  effects,  is  its  ability  to  produce  satisfactory  hardening 
of  the  gelatin  so  that  such  emulsions  may  be  washed  and  dried  with- 


316  D.  B.  ALNUTT  [j.  S.  M.  P.  E. 

out  damage.  Aluminum  or  chromium  compounds  have  been  most 
generally  used  in  acid-hardening  fixing  baths.  An  extensive  dis- 
cussion of  the  action  of  these  two  agents  and  of  the  theories  con- 
nected with  their  hardening  action  is  given  by  Sheppard,  Elliott, 
and  Sweet.10  Their  work  showed  that  the  efficiency  of  the  harden- 
ing action  of  the  alums  was  dependent  almost  entirely  on  the  £H  of 
the  solution  in  which  they  were  used.  It  follows  that  the  ability 
of  the  fixing  bath  to  maintain  the  proper  acidity,  even  with  con- 
tinual additions  of  alkali  carried  over  from  the  developer,  is  a  matter 
of  prime  importance  in  the  production  of  serviceable  fixing  bath 
formulas. 

Measurement  of  the  degree  of  hardening  of  any  particular  bath  on 
a  gelatin  emulsion  is  usually  made  by  determining  the  melting  point 
of  the  treated  emulsion.  One  of  the  oldest  and  most  commonly  used 
methods  of  determining  the  melting  points  of  gelatin  emulsions  is 
described  by  Crab  tree  and  Hartt.14  More  recently,  Woosley  and 
Pankhurst18  described  a  method  of  determining  melting  points 
which  appeared  to  us  to  have  greater  reproducibility.  Instead  of 
determining  the  melting  point  or  dispersal  point  of  the  gelatin  emul- 
sion simply  by  raising  the  temperature  of  a  water  bath  in  which  it 
was  immersed,  the  emulsion  was  continually  abraded  by  a  slight 
but  fairly  constant  pressure  from  a  rubber-tipped  stirring  rod. 
The  melting  point  determined  by  this  method  is  defined  as  the  lowest 
temperature  at  which  this  stroking  with  the  rubber-tipped  glass  rod 
first  produces  detachment  of  the  gelatin  from  the  film  base.  Melt- 
ing points  determined  by  such  a  method  are  several  degrees  below 
those  determined  by  the  older  method,  but  they  are  probably  more 
in  accordance  with  the  requirements  of  practice. 

In  order  to  determine  the  effect  of  various  periods  of  washing  and 
drying  upon  the  melting  point  of  the  hardened  emulsion,  strips  of 
film  developed  and  fixed  in  the  same  solutions,  at  the  same  time, 
were  given  different  periods  of  washing  and  were  allowed  to  dry  for 
different  periods  of  time.  The  results  indicated  that  washing  periods 
of  from  fifteen  minutes  to  120  minutes  and  drying  periods  of  from 
zero  to  twenty-four  hours  had  practically  no  effect  on  the  melting 
point  of  the  gelatin  emulsion.  Therefore,  in  most  cases,  melting 
point  tests  were  run  on  film  strips  either  immediately  after  washing 
or  after  a  short  drying  period.  It  is  possible  that  films  dried  over  a 
considerable  period  of  time  may  gain  slightly  in  hardness,  but  our 
experiments  indicated  that  melting  points  run  on  freshly  processed 


Oct.,  1943] 


AMMONIUM  THIOSULFATE  FIXING  BATHS 


317 


film  and  portions  of  the  same  film  kept  for  several  weeks  were  only 
a  few  degrees  different. 

In  Figs.  4  and  5,  the  ability  of  the  A  TF-1  and  A  TF-2  fixing  baths 


o    90 

o 

-    80 

H 
Z 

O    70 

o 

5    60 

hi 

5     50 


2         4          6         8         10        12        14 
c.c.oFMQ25/IOOc.c.ATF-l 
FIG.  4. 


o    90 

o 


60 


50 


24          6         8         10        12         14 

c.c.opMQ  25/  100  c.c.  ATF-2 

FIG.  5. 


6    x 
(L 


to  produce  hardening  when  contaminated  with  varied  amounts  of 
MQ25*  developer  is  illustrated  graphically.     It  will  be  noted  that 


*MQ25  Formula: 
Metol 

Sodium  sulfite 
Hydroquinone 


1.25gm          Sodium  carbonate,  anhyd.         25.00  gm 

75 . 00  gm          Potassium  bromide  1 . 5    gm 

4 . 75  gm          Water,  enough  to  make  1  liter 


318 


D.  B.  ALNUTT 


[J.  S.  M.  P.  E. 


the  ATF-1  formula  continues  to  produce  satisfactory  hardening 
even  after  the  £H  of  the  bath  has  attained  a  value  of  over  6,  whereas, 
in  common  with  other  chrome  alum  fixing  baths,  the  A  TF-2  formula 
rapidly  loses  its  hardening  action  as  the  plrL  approaches  5.  The 
inability  of  the  unbuffered  chrome  alum  bath  to  tolerate  more  than 
a  slight  amount  of  developer  contamination  is  also  apparent. 

In  developing  hardeners  for  ammonium  thiosulfate  fixing  baths, 
we  considered  it  also  desirable  for  the  hardener  to  have  rapid  action 
in  order  to  take  advantage  of  the  rapid  clearing  action  of  these  baths. 

Fig.  6  illustrates  graphically  the  speed  with  which  a  Super-XX 
emulsion  is  hardened  in  the  ATF-1  fixing  bath  and  in  the  ATF-2 
fixing  bath.  It  is  readily  apparent  that  the  chromium  bath  will 


« 90 

o 

-     80 

t- 

z 

2  ?o 

o 

|    60 

UJ 

S    50 


4          6          8         10        12 
FIXING    TIME    IN    MINUTES 

FIG.  6. 


14 


give  sufficient  hardening  for  the  proper  handling  of  the  film  within 
one  minute,  whereas  it  would  probably  be  advisable,  when  using 
the  A  TF-1  formula,  to  allow  the  film  to  remain  in  the  bath  from  2  to 
4  minutes.  In  general,  it  appears  that  aluminum-hardening  am- 
monium thiosulfate  fixing  baths  will  give  satisfactory  hardening 
within  twice  the  clearing  time. 

Fig.  7  shows  the  effect  of  use  on  the  rapidity  of  the  hardening 
action  of  the  A  TF-5  fixing  bath.  Super- JOT  film  is  hardened  more 
rapidly  in  a  used  fixing  bath  having  a  />H  of  5  than  in  a  fresh  bath. 
This  is  occasioned  by  the  fact  that  the  optimum  hardening  action  of 
an  aluminum  alum  fixing  bath  occurs  in  the  range  of  4.5  to  5.5  for 
ammonium  thiosulfate  fixing  baths,  so  that  the  rapidity  of  the  action 


Oct.,  1943]         AMMONIUM  THIOSULFATE  FIXING  BATHS 


319 


is  not  decreased  until  such  a  fixing  bath  is  near  its  exhaustion  point. 
Since  the  fresh  baths  have  a  pH  in  the  neighborhood  of  4.2,  optimum 
hardening  does  not  begin  until  use  of  the  bath  has  increased  its  pH 
to  the  effective  hardening  range. 

The  fact  that  addition  of  ammonium  salts  to  sodium  thiosulfate 
fixing  baths  increases  the  speed  of  fixation  has  been  long  known. 
C.  Welborne  Piper28  in  1914  found  that  a  concentration  of  4  per 
cent  ammonium  chloride  added  to  a  20  per  cent  sodium  thiosulfate 
fixing  bath  gave  the  optimum  reduction  in  clearing  time  for  the 
Lumiere  films  he  used.  Recently,  Crab  tree,  Muehler,  and  Russell13 
published  a  rapid-fixing  bath  formula,  designated  F-7,  using  50 


o    90 

e 

?    80 


0     70 

(L 


z    60 

5 

2     50 


I          23456789 

FIXING    TIME    IN    MINUTES 

•  FIG.  7. 

grams  of  ammonium  chloride  and  360  grams  of  sodium  thiosulfate 
per  liter.  They  also  suggested  the  addition  of  ammonium  chloride 
to  regular  sodium  thiosulfate  fixing  baths  in  amounts  of  5  per  cent 
for  the  purpose  of  increasing  the  rapidity  of  action  of  such  baths. 
They  pointed  out,  however,  that  additions  of  ammonium  chloride 
decreased  slightly  the  hardening  properties  of  such  baths.  There- 
fore, in  connection  with  the  investigation  of  the  hardening  properties 
of  the  ammonium  thiosulfate  fixing  baths,  it  was  thought  worth  while 
to  compare  the  hardening  action  of  a  typical  ammonium  thiosulfate 
fixing  bath  with  that  of  the  F-7  fixing  bath. 

The  curves  in  Fig.  8  represent  the  clearing  times  and  melting 
points  of  strips  of  Super-JOT  film  that  had  been  developed  in  MQ-25 


320 


D.  B.  ALNUTT 


[J.  S.  M.  P.  E. 


for  four  minutes  and  then  fixed  for  ten  minutes  each  in  a  50-cc  sample 
of  the  fixing  bath  tested.  This  procedure  was  the  same  as  that  used 
in  exhaustion  tests,  which  will  be  explained  in  detail  later.  As 
can  be  seen  from  the  curves,  the  hardening  properties  of  the  A  TF-1 
fixing  bath  are  considerably  better  than  those  of  the  F-7.  It  will 
also  be  observed  that  clearing  times  of  the  F-7t  although  short,  are 
not  so  short  as  those  of  the  ammonium  thiosulf  ate  bath. 

Blistering. — Blistering  of  film  is  a  rather  uncommon  occurrence 
when  the  more  modern  fixing  bath  formulas  are  used.  The  blister- 
ing of  emulsions  is  due  to  the  rapid  evolution  of  carbon  dioxide  gas 
from  the  reaction  of  the  sodium  carbonate  of  the  developer  with  the 
acid  of  the  fixing  bath.  If  the  processing  temperature  is  main- 


i 

!:  so 

UJ 

S 

40 


6    u 

5 1 

4    * 
,1 


I          <-> 


246          8         10        12        14        16         18       20       22 

NUMBER  OF  STRIPS 

FIG.  8.    ' 

tained  at  a  normal  level ;  if  the  amount  of  carbonate  in  the  developer 
is  not  excessive ;  and  if  the  pH  of  the  fixing  bath  in  use  is  not  too  low, 
this  accidental  blistering  is  very  unlikely  to  occur.  In  all  of  our 
testing  of  the  five  fixing  baths,  even  at  room  temperatures  of  around 
25  °C  (77  °F)  and  while  using  the  high  carbonate  D-19  developer, 
blistering  of  the  emulsion  was  never  noticed. 

Washing. — Extensive  comparative  experiments  between  an  F-5 
fixing  bath  and  the  A  TF-5  fixing  bath  indicated  that  the  thiosulf  ate 
was  eliminated  from  films  and  papers  at  approximately  the  same 
rate.  These  experiments  were  carried  out  by  fixing  a  4  X  5-inch 
sheet  of  either  film  or  paper  in  a  small  photographic  tray  for  a  ten- 
minute  period.  The  fixing  bath  was  drained  from  the  tray  and  the 


Oct.,  1943]         AMMONIUM  THIOSULFATE  FIXING  BATHS  321 

sheet  of  material  for  thirty  seconds  and  was  replaced  by  a  100-cc 
portion  of  distilled  water.  After  thirty  seconds  of  constant  agita- 
tion, this  first  wash  water  was  discarded  by  draining  the  tray  and 
the  material  for  thirty  seconds.  Then  a  second  100-cc  portion  of 
distilled  water  was  poured  into  the  tray  and,  after  a  one-minute 
period  of  constant  agitation,  this  second  wash  water  was  drained 
into  a  beaker  and  titrated  with  O.I  N  iodine  solution.  The  third 
wash  water  was  put  into  the  tray,  given  constant  agitation  for  two 
minutes,  drained,  and  titrated.  The  fourth  wash  water  was  allowed 
to  act  for  four  minutes;  the  fifth  wash  water  for  ninety  minutes. 
The  last  two  wash  waters  were  not  given  constant  agitation,  but  the 
tray  was  rocked  every  few  minutes.  Each  wash  water  was  titrated, 
and  the  amount  of  0.1  TV  iodine  consumed  was  used  as  a  measure 
of  the  amount  of  thiosulfate  removed  by  each  wash  water.  The 
rate  of  removal  of  the  two  fixing  agents  was  approximately  the  same. 

Sulfurization. — The  length  of  time  a  fixing  bath  can  be  stored  with- 
out precipitation  of  free  sulfur  is  called  its  sulfurization  life.  Since 
modern  fixing  baths  sometimes  have  sulfurization  lives  of  several 
months,  the  usual  practice14  is  to  store  samples  of  the  fixing  bath  to 
be  tested  in  glass-stoppered  bottles  at  elevated  temperatures.  Due 
to  their  high  acidity,  the  chrome  alum  fixing  baths  ATF-2  and 
ATF-3  sulfurize  rapidly.  Samples  of  ATF-4,  ATF-5,  F-5,  and  F-7 
were  stored,  both  at  room  temperature  and  at  40  °C  (104°F),  and 
remained  free  from  turbidity  for  four  weeks.  When  similarly  tested, 
the  ATF-1  fixing  bath  at  40°C  (104 °F)  showed  a  precipitate  of  free 
sulfur  in  one  week. 

Sludging. — The  property  of  a  fixing  bath  to  tolerate  quantities  of 
alkaline  developer  without  forming  a  sludge  of  aluminum  sulfite  is 
called  the  "sludging  propensity";  or  sometimes,  the  "developer 
toleration"  of  the  fixing  bath.  Since  in  practice  additions  of  de- 
veloper to  acid-hardening  fixing  baths  are  usually  made  at  very 
slow  rates,  the  common  method  of  carrying  out  this  test  has  been 
to  add  the  developer  slowly  to  the  fixing  bath  while  constantly  stir- 
ring, noting  the  amount  of  developer  which  first  causes  a  slight 
precipitate.  Although  this  method  has  been  used  for  some  time, 
Woosley  and  Pankhurst18  have  described  the  method  that  we  adopted 
for  one  type  of  sludge  test.  Their  definition  of  the  relative  sludge 
life  is  "the  number  of  cc  of  developer  necessary  to  cause  a  perma- 
nent opalescence  when  added  to  100  cc  of  the  fixing  bath  at  a  rate  of 
about  one  drop  per  two  seconds  while  constantly  stirring  at  65  °F," 


322  D.  B.  ALNUTT  [j.  s.  M.  P.  E. 

The  results  obtained  by  applying  this  test  to  the  fixing  baths  being 
compared  are  set  forth  in  Table  IV. 

TABLE  rv 

Relative  Sludge  Life  at  20° C  (68° F) 

ATF-l         ATP -4          ATF-5  F-5  F-7 

Original  pH  4.1  4.1  4.1  4.05  4.1 

/>H  at  sludge  point  7.1  8.1  7.9  7.8  7.7 

cc  MQ25  per  100  cc  bath  80-85     150-200     150-175     150-180     140-175 

With  this  type  of  test  no  sludging  occurs  even  at  200  cc  of  MQ25 
per  100  cc  of  bath  for  the  chrome  alum  baths.  It  will  be  noted  that 
ATF-4  and  ATF-5  compare  very  favorably  with  the  F-5  and  F-7 
baths,  whereas  the  A  TF-1  bath  has  a  lower  relative  sludge  life. 

Another  method  for  measuring  the  relative  sludge  life  of  a  fixing 
bath  has  been  used  by  Crabtree  and  Hartt,14  which  consists  in  add- 
ing various  amounts  of  developer  to  equal  portions  of  the  fixing 
baths  to  be  compared  and  storing  these  samples  at  an  elevated 
temperature.  The  results  of  this  type  of  test  for  sludging  propensity 
of  the  various  fixing  baths  are  given  in  Table  V.  These  results  are 
expressed  in  the  number  of  cc  of  MQ25  developer  which  were  toler- 
ated by  100  cc  of  a  fixing  bath  at  40°C  (104°F)  for  fifteen  days 
without  the  development  of  turbidity. 

TABLE  V 

Relative  Sludge  Life  at  40° C  (104° F} 

ATF-l       ATF-4         ATF-5          F-5  F-7 

cc  of  MQ25  per  100  cc  bath  16  32  32  22  26 

By  this  test  for  relative  sludge  life  the  chrome  alum  baths  A  TF-2 
and  ATF-3  failed  in  a  matter  of  four  days.  In  this  length  of  time 
a  turbidity  developed  in  the  chrome  alum  baths  whether  the  amount 
of  developer  added  was  large  or  small.  Here  again,  the  ATF-4  and 
ATF-5  baths  compare  favorably  with  F-5  and  F-7,  whereas  the 
A  TF-1  bath  has  a  slightly  lower  tolerance  for  carried-over  developer. 

Exhaustion  Tests. — Many  different  methods  have  been  proposed 
for  determining  the  exhaustion  point  of  fixing  baths.  One  of  the 
oldest  and  still  commonly  used  axioms  is,  "Discard  the  fixing  bath 
when  the  clearing  time  of  the  film  being  processed  becomes  twice 
as  long  as  it  was  in  the  fresh  fixing  bath. ' '  Theoretical  considerations 
involved  in  determining  the  exhaustion  point  of  a  fixing  bath  were 


Oct.,  1943]        AMMONIUM  THIOSULFATE  FIXING  BATHS  323 

published  by  Lumtere  and  Seyewetz29  in  1907.  At  that  time, 
through  a  study  of  the  solubility  of  silver  bromide  in  sodium  thio- 
sulfate,  they  proposed  a  test  for  recognizing  the  moment  when  a 
fixing  bath  should  be  discarded.  This  test  was  the  well  known  one 
of  exposing  a  drop  of  the  fixing  bath  on  a  filter  paper  to  strong  light 
and  humid  air.  If  this  spot  discolored,  the  fixing  bath  should  be 
discarded. 

Another  test  of  similar  nature  (depending  on  the  amount  of  dis- 
solved silver  in  the  fixing  bath)  was  attributed  to  Bayer  by  Clerk.30 
This  test  consisted  of  adding  10  cc  of  a  4  per  cent  solution  of  po- 
tassium bromide  to  100  cc  of  the  bath  under  test  and  noting  the 
formation  of  a  permanent  yellow  precipitate  which  was  assumed 
to  indicate  exhaustion  of  the  bath. 

Lumiere  and  Seyewetz20  in  1924  revised  their  ideas  on  the  ex- 
haustion point  of  fixing  baths  and  proposed  another  test  that  is 
probably  as  practical  as  one  can  use  for  determining  the  presence 
of  silver  salts  in  a  finished  emulsion.  This  test  used  a  drop  of  sodium 
sulfide  solution  (0.2  per  cent)  placed  directly  on  the  fixed  and  washed 
emulsion  under  test.  A  discoloration  of  the  emulsion  connoted  the 
use  of  an  exhausted  fixing  bath. 

None  of  these  tests  is  of  practical  value,  however,  if  the  fixing 
bath  loses  its  hardening  properties  before  it  has  reached  such  a  state 
of  exhaustion  as  to  be  discernible  by  them.  Furthermore,  in  many 
processing  installations  where  machine  processing  is  used,  the  in- 
creased time  of  fixation  becomes  the  limiting  factor  that  determines 
the  useful  life  of  the  fixing  bath. 

Rather  than  depend  upon  any  one  or  two  methods  of  measuring 
the  exhaustion  point  of  a  fixing  bath,  our  tests  were  designed  to  show 
the  melting  point  (hardening  action),  the  clearing  time,  and  the 
change  in  pH  of  each  bath  during  exhaustion.  The  spot  tests  on 
filter  paper  were  made  on  each  bath,  but  are  not  shown  in  graphic 
form.  Experiments  with  the  method  of  treating  the  fixed  film  with 
sodium  sulfide  solution  did  not  give  conclusive  evidence  of  the  ex- 
haustion point  of  the  bath;  so  they  were  not  continued  throughout 
the  series. 

Exhaustion  tests,  at  best,  are  comparative  only  when  done  on  a 
very  large  scale  and  under  practical  working  conditions.  There- 
fore, we  do  not  feel  that  the  results  of  the  experimental  exhaustion 
tests  can  be  applied  directly  to  practical  usage  in  determining  the 
amount  of  film  that  could  be  satisfactorily  processed  in  any  partic- 


324 


D.  B.  ALNUTT 


[J.  S.  M.  P.  E. 


ular  fixing  bath.  The  same  process  and  technique  were  used  on 
each  bath  and  every  precaution  was  taken  to  make  the  tests  com- 
parative. The  following  is  a  brief  outline  of  the  method  of  running 
the  exhaustion  tests : 

Eight-  by  ten-inch  sheets  of  Super-XX  cut  film  were  given  a  flash  exposure 
through  a  slit  negative  so  that  approximately  1/3  of  the  surface  of  the  film  was 
exposed.  This  sheet  was  then  cut  into  1  X  8- inch  strips  having  an  exposed  por- 
tion in  the  center  of  each  strip.  Only  50  cc  of  the  fixing  bath  to  be  tested  was 
used  for  each  exhaustion  test.  Each  strip  was  developed  for  four  minutes  in 
MQ25  developer  at  20°C  (68°F).  Then  the  strip  was  drained  for  five  seconds 
and  immersed  in  the  fixing  bath  at  20 °C  (68°F)  after  having  the  spot  of  fixing 


2 


-  2 


8          10          12         14         16 
NUMBER    OF    STRIPS 

FIG.  9. 


18 


20       22 


solution  applied  to  it,  as  described  under  clearing  time  tests.  The  clearing  time 
was  noted  and  the  strip  was  allowed  to  remain  in  the  fixing  bath  for  a  total  of 
ten  minutes  in  each  case. 

Then  the  strip  was  drained  for  five  seconds  and  washed  for  thirty  minutes  in 
water  at  20°C  (68°F).  After  washing,  the  melting  point  test,  as  described  under 
hardening  properties,  was  applied  to  each  strip.  Strip  after  strip  was  processed 
in  the  above  manner  using  the  same  50  cc  of  fixing  bath  until  its  />H  indicated  that 
the  bath  was  exhausted.  At  the  beginning  of  the  test  and  after  every  second  strip 
thereafter,  a  pH  was  run  on  the  fixing  bath.  All  pH  measurements  were  made  on 
a  Leeds  and  Northup  Low  Sodium  Glass  Electrode. 

The  results  of  the  comparative  exhaustion  tests  made  on  these 
fixing  baths  are  shown  in  graphs,  Figs.  9,  10,  and  "11.  As  may  be 


Oct.,  1943] 


AMMONIUM  THIOSULFATE  FIXING  BATHS 


325 


seen  from  Fig.  9,  the  F-5  is  the  only  formula  not  showing  rapid 
clearing  action.  In  each  case  the  ammonium  thiosulfate  fixing  baths 
give  somewhat  more  rapid  fixation  and  continued  to  give  this  rapid 
action  longer  than  does  the  combination  of  sodium  thiosulfate  and 
ammonium  chloride.  If  the  speed  of  fixation  is  used  as  the  limiting 
factor  in  the  useful  life  of  a  fixing  bath,  it  can  be  seen  that  A  TF-5 
should  give  the  longest  service  life.  ATF-1,  ATF-4,  and  F-7  should 
give  practically  equivalent  service  life  and,  of  course,  the  chrome 
alum  baths,  A  TF-2  and  A  TF-3,  would  fail  on  other  accounts. 

Fig.  10  gives  a  general  idea  of  the  hardening  properties  of  each  of 
these  fixing  baths  during  exhaustion.     The  chrome  alum  baths  give 


90 
u 

0     80 


70 


60 


50 


40 


8         10         12         14         16 
NUMBER    OF   STRIPS 

FlG.  10. 


18 


20       22 


excellent  hardening  for  the  first  few  strips,  but  rapidly  lose  their 
hardening  power,  as  their  acidity  is  lost  through  neutralization 
with  carried-over  alkali  from  the  developer.  The  ATF-1  contain- 
ing the  aluminum  chloride  hardening  agent  gives  much  better 
hardening  action  than  any  of  the  other  baths.  The  ATF-4  and 
AT  F-5  give  hardening  action  comparable  to  that  obtained  with  the 
F-5  formula.  As  will  be  noted,  the  hardening  action  of  the  am- 
monium chloride  F-7  formula  is  less  than  that  of  the  other  baths 
tested. 

Since  the  rate  at  which  the  developer  was  carried  over  into  the 
fixing  bath  was  practically  constant,  and  since  the  amount  and  type 


326 


D.  B.  ALNUTT 


[J.  S.  M.  P.  E. 


of  acidity  used  in  all  the  baths  except  the  chrome  alum  baths  were 
the  same,  the  pH  of  these  baths  during  exhaustion  would  be  expected 
to  rise  at  practically  the  same  rate.  As  can  be  seen  in  Fig.  11,  the 
baths  decreased  in  acidity  at  about  the  same  rate.  Naturally, 
the  lack  of  any  buffering  substance  in  the  chrome  alum  baths  gives 
them  a  low  tolerance  for  carried-over  alkali  and  the  />H  of  these  two 
baths  increased  more  rapidly. 

The  spot  test  was  made  during  the  exhaustion  of  each  of  these 
baths  by  placing  one  drop  of  the  fixing  bath  on  a  piece  of  white 
blotting  paper  after  each  strip  was  fixed.  At  the  conclusion  of  the 
tests,  these  spots  were  exposed  to  the  direct  rays  of  a  mercury  vapor 


2         4         6         8         10        12        14        16        18        20      22 
NUMBER   OF  STRIPS 

FIG.  11. 

lamp  for  a  period  of  four  hours.  This  exposure  was  found  to  be 
sufficient  to  develop  all  the  color  that  would  eventually  be  developed 
even  by  a  prolonged  exposure.  By  choosing  the  last  spot  that  did 
not  develop  color  with  this  test,  a  comparison  of  the  power  of  the 
fixing  bath  for  holding  dissolved  silver  in  a  non-staining  form  can 
be  obtained. 

The  results  of  these  spot  tests  were  somewhat  erratic  and  their 
meaning  is  not  entirely  clear,  since  it  is  possible  that  fixing  baths 
containing  enough  silver  to  show  stain  by  this  test  would  still  render 
the  silver  salts  in  an  emulsion  sufficiently  soluble  to  be  completely 
washed  out.  The  apparently  anomalous  results  of  these  tests  are 
shown  as  follows: 


Oct.,  1943]        AMMONIUM  THIOSULFATE  FIXING  BATHS  327 

A  TF-1  showed  color  after  the  10th  strip. 
A  TF-2  showed  color  after  the  2nd  strip. 
A  TF-3  showed  no  color  after  the  9th  strip. 
ATF-4  showed  color  after  the  8th  strip. 
A  TF-5  showed  color  after  the  12th  strip. 

F-5  showed  color  after  the  5th  strip. 

F-7  showed  color  after  the  18th  strip. 

Although  the  service  life  of  any  given  fixing  bath  depends  largely 
on  the  method  used  in  determining  its  exhaustion  point,  it  does 
appear  from  these  tests  that  any  of  the  ammonium  thiosulfate  fixing 
baths  can  be  expected  to  give  equal  or  better  service  life  than  com- 
monly used  sodium  thiosulfate  baths. 

ACKNOWLEDGMENT 

The  author  gratefully  acknowledges  the  suggestions,  advice,  and 
counsel  of  Dr.  J.  R.  Ruhoff,  and  the  assistance  of  other  members  of 
the  laboratory  staff  in  this  work. 

REFERENCES 

1  Private  communication. 

2  HERSCHEL,  SIR  JOHN  F.  W. :    Brewster's  Edinburgh  Philosophical  Journal 
(1819). 

3  SPILLER,  JOHN:  British  Journal  of  Photography  (June  15,  1866),  p.  284. 

4  SPILLER,  JOHN:  Photographisches  Archiv,  63  (1868). 
6  LABARRE:  Photographisches  Archiv,  374  (1892). 

6  VALENTA,  EDUARD:   Jahrbuchfuer  Photographic,  281  (1895). 

7  LIESEGANG,  EDUARD:  Photographic  Mosaics,  100  (1895). 

8  Photographische  Korrespondenz,  559  (1906). 

9  BAINES,  H.:  "Chemistry  of  Fixation,"  Phot.  J.,  69  (1929),  p.  314. 

10  SHEPPARD,  S,  E.,  ELLIOTT,  FELIX,  A.,  AND  SWEET,  S.  S.:   "Chemistry  of  the 
Acid  Fixing  Bath,"  /.  Franklin  Inst.,  196,  (1923),  p.  45. 

11  NEBLETTE,  C.  B.:    "Photography,  Its  Principles  and  Practice,"  Third  Ed., 
D.  Van  Nostrand  Co.,  New  York  (1938),  p.  333. 

12  KLEMPT,  W.,  BRODKORB,  F.,  AND  ERLBACH,  H.:   "Ammonium  Thiosulfate," 
Berichte  Gessellschaft  Kohlentechnik,  3  (1929-1931),  p.  493. 

13  CRABTREE,  J.  I.,  MUEHLER,  L.  E.,  AND  RUSSELL,  H.  D.:   "New  Stop  Bath 
and  Fixing  Bath  Formulas  and  Methods  for  Their  Revival,"  J.  Soc.  Mot.  Pict. 
Eng.,  XXXVm  (1942),  p.  353. 

14  CRABTREE,  J.  I.,  AND  HARTT,  H.  A.:    ''Some  Properties  of  Fixing  Baths," 
Trans.  SMPE,  XIH  (1929),  p.  364. 

16  MUEHLER,  LOWELL  E.:  "Liquid  Hardener  Solutions,"  U.  S.  Patent  No. 
1,981,426. 

16  BRUBAKER,  M.  M.:    "Photographic  Fixing  Compositions,"  U.  S.  Patent 
2,195,405. 

17  MARTIN,  E.  C.:    "Sulfamic  Acid,  a  New  Industrial  Chemical,"  Ind.  Eng. 
Chem.,  30  (1938),  p.  627. 


328  D.  B.  ALNUTT 

18  WOOSLEY,  D.  P.,  AND  PANKHURST,  K.  G.  A.:  "The  Use  of  Sodium  Hydrogen 
Sulphate  in  Acid  Hardening  Fixing  Baths,"  Phot.  J.,  82  (1942),  p.  12. 

19  BULLOCK,  E.  R.:    "On  Convection  Effects  in  Photographic  Bathing  Opera- 
tions," B.  J.  Phot.,  69  (1922),  p.  110. 

20  LUMIERE,  A.  AND  L.,  AND  SEYEWETZ,  A.:    "Fixing  Photographic  Plates: 
Limit  of  Usefulness  of  Fixing  Baths,"  Bull.  soc.  franc,  phot.,  11  (1924),  p.  66. 

21  WARWICK,  A.  W. :  "The  Laws  of  Fixation,"  Brit.  J.  Phot.,  64  (1917),  p.  617. 

22  PIPER,  C.  WELBORNE:    "The  Time  of  Fixation,"  Brit.  J.  Phot.,  60  (1913), 
p.  59. 

28  HANSON,  W.  T.,  JR.:  "The  Fixing  Process,"  Am.  Phot.,  36,  No.  3  (March, 
1942),  p.  22. 

24  SCHRAMM,  WALTER:  "The  Chemistry  and  Practice  of  the  Fixing  Process," 
Brit.  J.  Phot.,  82  (1935),  p.  360. 

26  SHEPPARD,  S.  E.,  AND  MEES,  C.  E.  K.:    "Investigations  on  the  Theory  of 
the  Photographic  Process,"  Longmans,  Green  and  Co.,  London,  p.  123. 

28  DAWSON,  G.  A.:  "Concentrated  Solutions:  A  New  Development  in  the 
Processing  of  X-Ray  Films,"  The  X-Ray  Tech.  (July,  1941),  p.  11. 

27  RUSSELL,  H.  D.  AND  CRABTREE,  J.  I.:  "Reducing  Action  of  Fixing  Baths  on 
the  Silver  Image,"  J.  Soc.  Mot.  Pict.  Eng.,  XVHI  (1932),  p.  371. 

28  PIPER,  C.  WELBORNE:    "Rapid  Fixing  Baths,"  Brit.  J.  Phot.,  61  (1914),  p. 
193. 

29  LUMIERE,  A.  AND  L.,  AND  SEYEWETZ,  A.:  "The  Exhaustion  Limits  of  Fixing 
Baths,"  Z.  Wiss.  Phot.,  5  (1907),  p.  317. 

30  CLERK,  L.  P.:    "Photography,  Theory  and  Practice,"  Pitman  Publishing 
Corp.,  New  York  (1937),  p.  276. 


THE  MOTION  PICTURE  IN  THE  SERVICE  OF  THE  ARMY 

AIR  FORCES* 

LAWRENCE  CARR** 

In  1937  the  Army  Air  Forces  started  its  training  film  program. 
Since  that  time  millions  of  feet  of  film  have  passed  through  hundreds 
of  projectors  and  have  been  seen  by  hundreds  of  thousands  of  Air 
Force  soldiers  from  the  lowest  yard  bird  to  the  brassiest  brass  hat. 

Our  training  film  program  is  designed  to  provide,  as  quickly  as  pos- 
sible, needed  materials  of  instruction  and,  at  the  same  time,  to  avoid 
unnecessary  duplication  of  similar  materials  being  produced  by  the 
Navy,  the  ground  forces,  the  British,  and  other  governmental  agencies. 

We  have  drawn  upon  the  services  of  many  specialists  in  the  motion 
picture  industry  to  work  closely  with  our  specialists  in  the  Air  Forces. 
By  effecting  such  combinations  of  talents,  it  has  been  possible  to 
produce  training  films  of  outstanding  instructional  effectiveness. 
Here  I  would  like  to  pay  tribute  to  the  many  individuals  who  have 
given  so  generously  of  their  professional  skills  and  equipment  in  the 
development  of  Army  Air  Forces  training  films.  I  know  particularly 
of  the  fine  work  done  by  Col.  Keighley  of  the  AAF,  and  Maj.  Cowling 
whom  you  all  know.  I  believe  he  has  been  for  some  years  an  officer 
of  this  organization. 

It  is  General  Arnold's  wish  that  the  training  film  program  be  inte- 
grated with  the  instructional  courses  being  given  within  the  Air 
Forces.  Courses  of  study  are  analyzed  to  find  subject  matter  that 
can  be  presented  to  good  advantage  in  motion  picture  form.  Con- 
tinuous contacts  are  maintained  with  instructors  in  this  country  and 
abroad  so  that  the  training  problems  may  be  considered  from  the 
standpoint  of  instructor  and  trainee. 

There  has  existed  a  need  for  a  central  agency  within  the  Army  Air 
Forces  to  coordinate  the  development  of  the  training  film  program. 
Recognition  of  this  is  one  of  the  reasons  why  the  Training  Aids 
Division  of  the  Army  Air  Forces  has  been  organized.  Our  offices  will 


*  Presented  at  the  1943  Spring  Meeting  at  New  York. 
**  Colonel,  Training  Aids  Division,  Army  Air  Forces,  Washington. 


329 


330  L.  CARR  [j.  s.  M.  p.  E. 

be  maintained  at  One  Park  Avenue,  New  York  City,  after  May  20, 
1943.  The  training  film  section  of  Training  Aids  is  staffed  with  offi- 
cers and  enlisted  personnel  familiar  with  the  motion  picture  industry. 

Our  problems  with  training  films  can  be  divided  roughly  into  three 
parts:  they  are  concerned  with  production,  distribution,  and  proper 
utilization  of  films. 

There  are  hundreds  of  films  used  in  Air  Forces  instruction,  cover- 
ing such  subjects  as  flight  instruction,  gunnery,  bombardment,  air- 
craft detection  and  recognition,  navigation,  intelligence  procedures, 
and  many  other  allied  subjects,  as  well  as  films  about  engines,  para- 
chutes, brakes,  instruments,  photography,  communication  systems, 
and  inspection  procedures. 

There  are  more  technical  than  tactical  films  due  to  the  relative 
stability  of  these  subjects.  With  the  changing  or  conflicting  doctrines 
of  tactics,  such  film  materials  sometimes  become  obsolete  before  they 
are  completed. 

General  rules  in  deciding  what  films  are  to  be  produced  are :  first, 
the  relative  importance  of  the  subject  to  the  training  activities; 
second,  the  suitability  of  the  subject  matter;  and  third,  the  produc- 
tion requirements  with  reference  to  military  personnel,  materials, 
and  equipment. 

After  approval  for  production  a  study  is  made  to  determine  what 
elements  of  the  sound  motion  picture  should  be  employed  to  simplify 
the  concepts  involved.  Will  it  be  animation  to  clarify  abstractions  or 
complex  movements,  or  will  it  be  ultra-rapid  photography  to  study 
opaque  objects  and  movements?  Maybe  photomicrography  is 
needed  to  reveal  material  stress  and  strain.  Color  is  important,  of 
course,  for  medical  and  camouflage  subjects. 

Production  units  are  maintained  at  Wright  Field,  Dayton,  Ohio,  for 
the  production  of  training  films  dealing  with  mechanical  and  elec- 
trical equipment.  Wright  Field  is  the  heart  of  the  aeronautical  re- 
search activities  of  the  Air  Forces.  Other  facilities  are  at  Culver  City, 
California,  where  the  AAF  first  motion  picture  unit  is  located.  This 
organization  has  recently  produced  such  films  as  Learn  and  Live, 
Swim  and  Live,  How  to  Fly  the  B-26,  the  film  you  will  see  upon  the 
completion  of  this  talk,  Straight  and  Level  Flights  and  The  Identifica- 
tion of  the  Jap  Zero. 

Another  important  source  of  films  is  the  aircraft  equipment  manu- 
facturers.   They  prepare,  through  their  own  facilities  and  after  co 
ordination  with  training  aids,  films  on  the  installation,  operation,  and 
servicing  of  their  equipment. 


Oct.,  1943]        MOTION  PICTURES  AND  ARMY  AIR  FORCE  331 

After  an  Army  Air  Forces  training  film  has  been  completed  and  has 
the  approval  of  qualified  technical  authorities,  it  is  released  for  distri- 
bution to  Army  Air  Forces  stations  both  at  home  and  abroad.  Distri- 
bution needs  are  determined  through  the  training  sections  of  the 
various  Commands  and  Air  Forces.  A  composite  order  is  then  given 
to  commercial  laboratories  for  the  needed  number  of  prints.  The 
prints  are  sent  directly  from  the  laboratory  to  the  using  stations. 
Sixteen-millimeter  prints  are  used  almost  exclusively.  At  present,  an 
average  of  about  250  prints  of  each  Army  Air  Forces  training  film  is 
distributed.  At  first  thought,  this  number  may  seem  great,  but  we 
consider  training  films  and  reference  materials  similar  to  field  manuals, 
books,  technical  orders  and  other  publications,  and  believe  these 
films  should  be  available  for  use  from  local  station  libraries.  If  only 
one  trainee  were  to  get  one  idea  that  would  prevent  one  casualty  or 
destruction  of  one  airplane,  the  cost  of  the  film  would  be  entirely 
liquidated. 

There  are  techniques  for  the  use  of  training  films  as  there  are  for 
their  production.  We  are  preparing  instructor's  manuals  for  Air 
Force  films.  These  manuals  include  a  detailed  description  of  the 
film,  suggestions  for  its  use,  reading  references,  and  objective  test 
questions. 

The  instructor  can  make  or  break  the  usefulness  of  a  film.  The 
idea  that  large  groups  can  be  exposed  to  training  films  and  come  away 
with  a  mastery  of  the  content  is  erroneous,  and  it  is  one  of  the  aims  of 
the  Training  Aids  Division  to  point  this  out  to  users.  Then,  too,  the 
use  of  films  unrelated  to  the  instructional  problem  at  hand  is  dis- 
couraged; likewise,  the  showing  of  more  than  one  film  of  ten  or 
fifteen  minutes  in  any  one  period.  Films  requiring  longer  projection 
periods  are  shown  in  short  sequences.  Particular  attention  must  be 
paid  to  the  physical  conditions  under  which  films  are  shown.  It  is,  of 
course,  deadly  to  show  films  immediately  §after  eating  or  in  a  room 
inadequately  darkened  and  ventilated. 

In  order  that  the  same  degree  of  supervision  and  coordination 
which  is  realized  in  the  preparation  and  production  of  training  films 
may  be  exercised  in  their  use,  especially  trained  officers  are  assigned 
to  help  Army  Air  Forces  stations  obtain  training  film  materials  suited 
to  their  particular  needs. 

We  are  firmly  convinced  that  by  carefully  planning  the  production, 
distribution,  and  use  of  training  films,  the  value  inherent  in  the  pro- 
gram can  be  made  to  contribute  to  the  successful  prosecution  of  the 
war  effort. 


A  COMPACT  PRODUCTION  UNIT  FOR  SPECIALIZED  FILM* 
O.  W.  HUNGERFORD** 


Summary. — This  paper  outlines  a  few  short  cuts  in  the  use  of  16-mm  film  for 
specialized  film  production  with  a  minimum  of  personnel.  Certain  features  of  the 
setup  have  reduced  man-hours  to  a  minimum  and  have  made  a  compact,  yet  thoroughly 
efficient,  unit  for  the  production  of  secret  and  timely  subjects. 

The  war  has  brought  about  many  changes  and  new  ideas.  Among 
these  was  the  overnight  recognition  of  the  sound  motion  picture 
as  an  efficient  medium  for  training  and  for  presenting  facts  and  data 
in  predigested  form.  While  much  has  been  written  about  the  large- 
scale  training  film  production  programs  that  are  under  way,  little 
has  been  said  about  the  small,  yet  complete  and  self-contained  pro- 
duction units  whose  purpose  it  is  to  present  facts  and  data  in  most 
concise  form.  This  paper  will  outline  such  a  production  unit. 

For  security  and  related  reasons,  it  is  usually  essential  that  the 
operating  personnel  of  such  units  be  kept  at  an  absolute  minimum, 
yet  the  finished  product  must  be  one  of  highest  technical  quality. 
From  the  standpoint  of  equipment,  a  requirement  of  this  kind  auto- 
matically dictates  16-mm  professional  machinery;  it  also  dictates 
extreme  versatility  in  the  various  persons  needed  to  operate  this 
equipment.  In  such  an  organization  it  is  not  uncommon  that  each 
person  will  be  able  to  act  as  cameraman,  sound  recordist,  film  editor, 
special-effects  man,  printer,  and  even  projectionist  as  the  need  may 
arise.  In  other  words,  the  members  of  the  staff  are  capable  of 
"doubling  in  brass."  It  is  this  ability  together  with  the  reliability, 
simplicity,  and  precision  of  the  machinery  chosen  that  makes  the 
results  possible. 

CAMERA     EQUIPMENT 

The  camera  equipment  includes  a  Maurer  professional  sound  cam- 
era for  studio  and  general  tripod  work.  This  camera  has  pilot-pin 

*  Presented  at  the  1943  Spring  Meeting  at  New  York. 
**  Washington,  D.  C. 
332 


PRODUCTION  UNIT  FOR  SPECIALIZED  FILM  333 

registration  and  has  the  pull-down  claw  located  right  at  the  base  of 
the  picture  aperture,  eliminating  that  difficulty  so  common  to  the 
magazine-chamber  type  of  camera,  frame  line  shift.  This  camera  can 
be  wound  back  for  double-exposure  effect  and  for  lap  dissolve. 

For  studio  work  it  is  especially  convenient  that  all  lenses  supplied 
for  it  have  been  standardized  at  the  SMPE  standard  distance  be- 
tween the  image  on  the  film  surface  and  the  mounting  shoulder  of  the 
lens.  All  three  lens  openings  in  the  turret  have  been  standardized 
at  this  standard  distance.  Any  standardized  lens  can  be  placed  in 
any  lens  hole.  It  will  focus  perfectly  in  all  three.  It  is  interesting 
to  note  that  as  much  as  three  to  five  thousandths  of  an  inch  has  to  be 
taken  off  the  lens  shoulder  to  standardize  the  lens.  This  extra  allow- 
ance is  left  on  the  lens  mount  by  the  lens  manufacturer  because  the 
film  in  the  usual  loose-gate  camera  bellies  away  from  the  lens  by 
approximately  this  distance.  We  have  also  adapted  this  camera  to 
a  stop-motion  device  for  use  on  a  title  stand. 

The  animation  stand  is  equipped  with  an  Eastman  Cine*-Special 
camera  adapted  to  animation  by  the  installation  of  a  calibrated 
movement  of  the  shutter  so  that  accurate  dissolves  may  be  obtained 
up  to  64  frames.  This  camera  is  also  equipped  with  a  stop-motion 
motor  for  either  forward  or  reverse  motion,  and  a  direct  frame- 
reading  counter  that  is  reversible  so  that  regardless  of  the  direction 
of  travel  of  the  film  the  counter  may  be  read  forward.  We  use  this 
camera  on  the  technique  known  as  "scratch-off"  which  we  call  our 
"3-2  method."  This  is  simply  running  the  camera  backward  three 
frames,  then  twice  forward  taking  the  picture  on  the  second  forward 
motion.  In  this  way  we  are  always  able  to  maintain  the  same  frame 
line.  The  effect  stand  for  animation  while  quite  simple  is  capable 
of  almost  any  type  of  action  requiring  little  time  in  man-hours  of 
operation. 

We  have  set  up  a  standard  for  our  Graphic  Division  for  cell  ani- 
mation with  two  standard  sizes  of  cells  known  as  our  A  cell,  which  is 
10  X  12V2  inches,  and  our  B  cell,  which  is  20  X  25  inches.  These 
cells  are  punched  with  a  three-hole  punch,  the  center  hole  being 
L/4  inch  round  and  the  two  side  pins  being  ]/8  inch  wide  and  ap- 
proximately 1/2  inch  long,  spaced  4  inches  from  the  center  pin.  This 
size  of  punching  has  been  adopted  by  the  Navy  Photo-Science 
Laboratory  as  their  standard  and  for  convenience  we  have  also 
adopted  it.  A  great  deal  of  animation  work  is  also  carried  on  in  the 
old  but  very  often  forgotten  technique  of  the  cardboard  cut-out 


334  O.  W.  HUNGERFORD  [J.  S.  M.  P.  E. 

model  and  its  counterpart.  We  have  found  that  this  type  of  pro- 
cedure speeds  up  certain  animation  technique.  Approximately  90 
per  cent  of  our  work  deals  with  animation,  and  almost  100  per 
cent  of  our  animation  is  shot  on  Kodachrome  Type  A  using  C.  P. 
bulbs  for  illumination. 

SOUND     EQUIPMENT 

It  is  in  this  department  that  equipment  flexibility  and  compactness 
are  evident.  The  basis  of  our  16-mm  recording  equipment  is  a 
Maurer  Model  D  Sound  Recorder  -with  the  usual  noise-reduction 
equipment.  The  amplification  equipment  is  rack-mounted  with 
jumping-plug  contacts  for  immediately  locating  any  difficulty  that 
might  arise  in  the  equipment.  The  mixing  equipment  has  an  8- 
channel  input  with  four  active  lines.  These  are  permanently  con- 
tact-jumped from  two  microphone  inputs  and  two  turntable  pick-ups. 
The  amplification  equipment  is  set  up  for  film  recording,  disk  record- 
ing or  re-recording  from  either  disk  or  film.  The  disk  reproducing 
equipment  is  designed  to  operate  at  either  33  or  78  rpm.  The  pick- 
ups are  Western  Electric  9A  which  may  be  used  for  either  hill-and- 
dale  or  lateral  recordings.  The  disk  recorder  is  a  Presto  which  is 
suitable  for  either  33  or  78-rpm  operation.  The  film -phonograph 
equipment  consists  of  two  35-mm  film-phonographs  and  one  Maurer 
16-mm  film-phonograph.  This  latter  equipment  has  proved  to  be  a 
reliable  and  useful  machine  for  many  purposes  other  than  re-record- 
ing. Very  often  it  is  necessary  to  check  the  quality  of  commercially 
produced  prints.  This  is  quite  simple  as  the  system  has  a  consistent 
and  very  low  noise-level  and  the  frequency  characteristics  of  the 
channel  remain  the  same  from  day  to  day.  Our  projection  equip- 
ment consists  of  a  Bell  &  Howell  750-watt  projector  that  we  have 
rebuilt  to  hold  a  1000-watt  bulb,  and  in  which  we  have  installed  a 
special  preamplifier  so  that  its  output  may  be  fed  directly  into  our 
rack-amplifier  for  quality  reproduction.  We  are  now  using  a  Jensen 
coaxial  wide-range  loud-speaker  for  reproduction  with  this  system. 
At  some  later  date  we  hope  to  install  a  good  two-way  reproducer  for 
this  channel,  such  as  a  Jensen  Type  E.  When  one  becomes  accus- 
tomed to  a  system  of  this  sort  the  use  of  a  conventional  projector  to 
reproduce,  for  instance,  a  Kodachrome  duplicate  is  rather  a  blow. 
Such  an  arrangement  as  ours  makes  it  very  easy  to  discriminate  be- 
tween good  and  bad  prints. 


Oct.,  1943]        PRODUCTION  UNIT  FOR  SPECIALIZED  FILM  335 

EDITING  AND  EDITING  EQUIPMENT 

Since  most  of  the  fact  and  data  films  are  built  to  order,  so  to  speak, 
very  little  editing  is  necessary.  Often  the  sound  is  made  prior  to  the 
actual  shooting  of  animation.  Therefore  the  animation  action  can 
be  accurately  timed  to  the  voice.  In  a  composite  picture  in  which 
we  use  both  live  acting  or  clip  shots  with  animation  and  occasionally 
a  live  synchronized  shot,  the  film  is  recorded  after  the  assembly 
process.  Since  these  films  are  made  with  the  intention  of  being 
informative  rather  than  entertaining  or  "arty,"  editing  of  them  is 
relatively  a  simple  job.  It  must  be  so,  for  if  the  shots  were  com- 
plicated by  all  sorts  of  angles,  crosscuts,  sound-effects,  etc.,  this  set-up 
would  defeat  its  purpose.  If  organizations  of  this  kind  were  to  think 
of  individualism,  which  might  be  called  the  niceties,  of  technical  pro- 
duction, we  would  be  compelled  to  set  the  idea  aside  owing  to  the 
unwarranted  diversion  of  man-hours  required  for  this  type  of  "arty" 
production. 

In  conclusion,  let  me  leave  this  thought  with  you:  while  major 
emphasis  must  be  placed  on  the  large  training  film  project  using  a 
great  many  specialists  who  need  no  skill  beyond  their  own  particular 
field,  small,  compact,  highly  versatile  production  teams  skilled  in  all 
of  the  essential  elements  of  production  make  up  the  personality  of 
these  "facts-and-figures"  units  that  are  doing  their  bit  very  quietly  in 
this  war.  The  nature  of  the  material  being  portrayed  in  such  films 
must  remain  a  military  secret.  Their  importance,  however,  can  not 
be  overlooked. 


DISCUSSION  OF  INDUSTRY  PROBLEMS* 


ED  KUYKENDALL** 

I  am  delighted  to  be  able  to  participate  in  the  annual  get-together 
meeting  of  such  able  men  who  constitute  the  Society  of  Motion 
Picture  Engineers.  You,  gentlemen,  are  a  most  vital  part  of  a  great 
industry,  an  industry  that  has  made  tremendous  progress  over  a 
period  of  years.  You,  who  have  contributed  so  much  to  the  forward 
movement  of  the  motion  picture  industry,  are  to  be  congratulated 
not  only  for  your  ability  but  for  your  complete  determination  to 
move  forward  and  better  the  all-round  development  of  the  motion 
picture. 

The  Motion  Picture  Theatre  Owners  of  America,  which  is  the 
largest  and  oldest  trade  association,  has  the  same  interests  at  heart 
as  you  engineers — the  development  of  the  industry;  that  they 
through  their  theaters  can  best  and  most  intelligently  serve  the 
public  which,  after  all,  is  entitled  to  nothing  less. 

Over  a  period  of  years  I  have  watched  the  growth  and  accomplish- 
ments of  your  organization.  You  have  gone  forward  every  minute 
of  the  time.  The  marks  of  your  accomplishments  are  definitely 
visible  in  and  about  the  theaters  in  this  good  old  U.  S.  A.  You  have 
made  it  possible  for  us,  the  theater  owners,  to  keep  abreast  of  the 
times — modern  times,  if  you  please.  You  have,  in  your  eiforts,  made 
it  possible  for  our  theaters  to  be  emblems  of  modern  progressiveness, 
and  as  the  public,  as  well  as  theater  management,  walk  into  places  of 
amusement  the  results  of  your  ingenuity  and  hard  work  can  be  seen 
readily  from  all  sides.  It  gives  me  great  personal  satisfaction  to 
realize  that  the  theater  owner  is  exploiting  your  brain  child  to  the 
fullest. 

Still,  the  theater  has  a  long  way  to  go  in  progressive  development; 
so  far  to  go  yet  that  we  are  hesitant  in  looking  down  the  road  with 
its  many  curves  and  bad  crossings.  But  together,  arm  in  arm,  we 

*  Presented  at  the  1943  Spring  Meeting  at  New  York. 
**  President,  Motion  Picture  Theatre  Owners  of  America. 
336 


DISCUSSION  OF  INDUSTRY  PROBLEMS  337 

will  continue  the  forward  march  of  development  and  progress  which 
the  public  will  surely  recognize  and  show  their  appreciation  at  the 
old  box-office. 

The  all-out  war  in  which  we  are  now  engaged  has  had  its  hard 
touch  on  motion  pictures.  Many  of  us  are  not  too  happy  with  the 
results  of  government  regulation.  Many  of  us  will  undoubtedly  say 
we  would  have  done  this  and  that  differently.  Many  times  I  am 
confused  and  wonder  what  it  will  lead  to,  but  as  I  sit  down  and  take 
inventory  of  the  general  picture,  it  seems  to  me  that  we,  as  an  in- 
dustry, have  suffered  less  than  most  other  businesses. 

The  MPTOA  was  the  first  to  emphasize  the  necessity  of  keeping 
the  theaters  open  during  the  stress  of  war,  regardless  of  hardships 
and  regulations.  This  is  our  first  duty  to  the  public — we  can  accept 
no  other  attitude.  Motion  picture  entertainment  is  essential  to  the 
levelness  of  our  war-conscious  minds. 

In  selling  War  Bonds,  doing  relief  work,  and  conducting  general 
patriotic  efforts,  we  put  forth  every  possible  effort,  and  the  results 
have  been  most  gratifying.  We  are  proud  of  this  work,  but  it  is  no 
more  than  we  should  do  as  good  Americans.  In  fact,  it  is  as  little  as 
we  should  do.  My  slogan  has  been,  "The  most  we  can  do,  is  the 
least  we  should  do."  I  am  no  believer  in  using  what  we  have  done 
in  our  effort  to  get  governmental  consideration,  but  I  am  all  out  in 
making  every  possible  fight  to  get  what  justly  belongs  to  us  in  this 
confused  and  hurried  world.  It  is  my  belief  that  we  should  fight  to 
the  limit  any  attempt  or  thought  to  pass  us  by.  We  owe  that  to 
those  who  have  invested  all  they  possess  in  our  industry,  and  fight 
we  will  for  our  rights — nothing  more,  nothing  less. 

Adapting  theaters  to  wartime  restrictions  is  a  matter  of  vital  im- 
portance not  only  to  theater  owners,  but  to  you  of  the  Engineers. 
In  this  day  of  priorities  over  almost  everything,  we  can  not  continue 
on  the  old  basis,  but  must  accept  the  all-out  war  theme  and  learn  to 
do  without  certain  materials  in  this  emergency.  You  of  the  En- 
gineers, and  we  of  the  theater,  must  use  our  ingenuity  to  continue 
operations  of  our  theaters,  maybe  under  restrictions,  probably  with 
hardships,  but  do  it  we  will.  But,  while  we  are  doing  this,  we  are 
learning  many  things  that  will  stay  with  us  long  after  we  have 
knocked  hell  out  of  the  Axis! 

I  can  not  put  too  much  faith  in  the  return  of  former  employees. 
In  my  mind,  our  industry  will  never  be  classified  as  essential  to  the 
war  effort,  but  we  have  not  been  declared  non-essential.  We  are  in 


338  E.  KUYKENDALL  [J.  S.  M.  P.  E. 

the  twilight  zone,  and  our  industry  is  being  judged  now  on  a  purely 
individual  basis.  So  it  seems  like  wishful  thinking  to  sit  by  and  hope 
that  former,  gifted  employees  will  be  sent  back  to  us  to  resume  im- 
portant work  before  this  fight  to  the  death  is  over.  So  let  us  who 
are  still  on  the  job  work  harder  as  individuals:  improvise,  create, 
train  women,  use  older  men.  We,  as  an  industry,  do  not  want  to 
do  anything  less  than  our  full  part  in  this  war. 

It  is  my  opinion  that  the  War  Activities  Committee  should  be  given 
every  possible  support  by  this  entire  industry.  The  MPTOA  has 
cooperated  with  this  committee  as  individuals,  and  not  as  an  organi- 
zation. This  precludes  exhibitor  politics.  We,  who  have  been 
placed  on  this  committee,  are  proud  to  serve  with  it,  and  we  believe 
that  the  War  Activities  Committee  is  the  only  one  that  could,  and 
has,  functioned  for  the  entire  industry. 

I  have  noted  criticism  from  one  source  about  too  much  flag  waving 
in  the  theaters.  I  go  on  record,  personally,  as  not  agreeing  with  this 
thought.  I  believe  it  is  our  duty  as  an  industry  to  see  to  it  that 
our  beloved  flag  is  waved  in  any  and  all  places.  It  inspires  confi- 
dence, gives  us  a  concrete  encouragement:  an  emblem  of  the  Ameri- 
can way  of  life,  may  it  ever  wave,  and  may  we,  as  an  industry,  leave 
nothing  undone  to  insure  that  its  waving  continues. 

I  like  the  name  of  your  organization,  "Engineers,"  meaning 
planners,  devisers,  creators,  progressive  thinkers,  carrying  on  for  the 
whole  industry;  and  the  engineers  are  vital  parts  of  this  war  effort 
outside  this  industry. 

We  will  continue  to  have  our  industry  worries.  We  will  continue 
to  feel  as  an  industry,  and  as  individuals,  that  we  are  not  getting  our 
just  dues  during  the  stress  of  war.  But  let's  keep  mindful  of  the 
fact  that  it's  because  of  war,  and  that  we  must  keep  ourselves  more 
on  the  alert  to  protect  our  fair  interest.  It  means  more  work  for  all 
of  us,  but  that's  no  more  than  we  can  expect  under  present  conditions. 

There  are  many  things,  technically  and  otherwise,  I  could  have 
discussed  with  you.  All  are  important  and  cover  many  of  your 
varied  activities,  but  time  prohibits  and  this  is  no  place  for  a  speech . 

But  if,  in  winning  this  war,  we  lose  sight  of  the  American  principles 
and  way  of  life,  we  have  gained  very  little,  and  would  be  very  un- 
happy after  it  was  all  over.  So  you  and  I,  as  Americans  first,  and  an 
industry  afterward,  have  a  big  job  before  us  which  we  accept  with 
the  full  importance  of  its  meaning. 

It  is  regrettable  that  there  are  quite  a  few  among  us  who  have 


Oct.,  1943]  DISCUSSION  OF  INDUSTRY  PROBLEMS  339 

allowed  the  dollar  mark  to  obscure  their  vision  of  the  future  and  their 
obligation  to  America.  They  are  blinded  by  the  collection  of  more 
dollars,  and  are  prone  to  allow  themselves  to  see  only  the  monetary 
gains  of  immediate  days.  But  I  warn  them :  stormy  days  are  ahead 
for  such  minds;  fairness  will  be  forced  on  them  whether  they  like  it 
or  not.  They  may  find  that  their  immediate  financial  advantages 
may  be  snatched  away  from  them  as  there  can  be  only  one  way  for  us 
to  conduct  ourselves:  fairness  in  our  relations  with  each  other  and 
patriotic  and  wholehearted  effort  for  our  government.  It's  the  one 
and  only  way  you  and  I  can  hope  to  be  happy  and  satisfied  with  our- 
selves, and  really  enjoy,  personally,  what  we  are  doing. 

Let's  you  and  I — all  of  us — keep  our  balance,  continue  to  work 
harder  and  harder  for  a  continuance  of  our  present  way  of  life ;  allow 
nothing,  or  anything,  or  anybody,  to  change  our  course,  that  you,  the 
Society  of  Motion  Picture  Engineers,  and  we,  The  Motion  Picture 
Theatre  Owners  of  America,  can  walk  together  down  the  highway  of 
life  with  the  collective  knowledge  that  we  did  our  part,  honestly,  sin- 
cerely, and  can  look  the  boys  full  in  the  face  on  their  return,  knowing 
that  we,  too,  have  done  our  part  as  Americans. 


SOME  SUGGESTED  STANDARDS  FOR  DIREC 
16-MM  PRODUCTION* 

LLOYD  THOMPSON** 


Summary. — An  increase  in  the  use  of  direct  16-mm  production  makes  it  desirable 
that  certain  standards  be  set  up  in  order  that  all  producers  be  able  to  follow  definite 
procedures.  If  such  standards  can  be  agreed  upon  it  will  make  it  much  easier  for  the 
producer  to  do  his  work  and  train  his  help.  It  will  allow  the  equipment  manufacturer 
to  produce  better  machines  to  handle  16-mm.  It  will  allow  the  laboratories  to  give 
better  prints  with  a  minimum  of  delay  and  a  minimum  of  error.  The  standards  that 
are  suggested  should  be  studied  closely  by  those  interested  and  suggestions  made. 

The  increased  use  of  direct  production  of  16-mm  film  for  both 
sound  and  photography  makes  it  highly  desirable  that  certain  stand- 
ards be  adopted  covering  the  correct  procedures  to  be  used.  As  long 
as  only  a  few  persons  or  companies  were  producing  direct  16-mm  films, 
standards  were  not  too  important  because  procedures  were  used  that 
were  found  by  experience  to  be  satisfactory.  However,  when  a  large 
number  of  persons  or  companies  start  using  16-mm  film  for  commer- 
cial exhibition,  it  becomes  important  that  certain  standards  be  adopted. 
Unless  this  is  done,  it  will  be  difficult  to  find  technicians  who  are  ca- 
pable of  working  with  different  companies  and  almost  impossible  for 
the  producers  to  secure  good  laboratory  service,  and  the  equipment 
manufacturers  will  be  unable  to  build  any  sort  of  professional  equip- 
ment that  will  satisfy  any  great  number  of  users. 

Before  any  standards  are  adopted,  however,  it  is  necessary  to  find 
out  what  is  needed  and  what  experience  has  shown  will  work.  It  is 
always  hard  for  a  new  industry  to  set  standards  because  improve- 
ments are  constantly  being  made.  Today's  standard  may  be  obso- 
lete tomorrow.  All  of  us  can  remember  the  beginning  of  radio  and  the 
development  that  has  since  taken  place.  Today  one  might  say  that 
the  standards  are  set,  but  frequency  modulation  will  probably  demand 
new  standards.  Therefore,  any  standards  proposed  in  this  paper 

*  Presented  at  the  1943  Spring  Meeting  at  New  York. 
**  The  Calvin  Co..  Kansas  City,  Mo. 
340 


DIRECT  16-MM  PRODUCTION  341 

should  probably  come  under  the  name  of  Recommended  Practices, 
but  there  must  be  a  beginning. 

Direct  16-mm  production,  to  be  successful,  depends  upon  good  lab- 
oratory service.  There  are  several  organizations  with  reputations 
for  doing  good  laboratory  work,  but  even  these  concerns  are  not  in 
complete  agreement  as  regards  processing  methods. 

The  problem  of  emulsion  position  has  been  previously  discussed  in 
the  JOURNAL1  and  has  been  well  covered.  Two  standards  are  being 
used  today:  The  emulsion  may  face  either  the  light-source  or  the 
lens.  As  far  as  picture  position  is  concerned,  one  is  as  good  as  the 
other,  because  the  lens  may  be  manually  focused  for  either  emulsion 
position.  However,  sound  is  played  often  on  a  projector  that  does 
not  allow  focusing  of  the  sound-track,  and  this  can  result  in  a  differ- 
ence in  sound  quality  depending  upon  the  position  of  the  emulsion 
with  respect  to  the  lens.  I  say  there  can  be  a  difference  because  most 
persons  will  not  be  able  to  tell  whether  the  sound-track  is  in  or  out  of 
focus  as  they  listen  to  a  large  number  of  the  prints  being  distributed 
today.  On  a  really  good  sound  print  there  is  a  difference,  but  if  the 
sound-track  is  really  good  it  will  give  satisfactory  reproduction  on  an 
average  projector  without  the  focusing  arrangement. 

Some  producers  and  some  editors  produce  pictures  with  large  num- 
bers of  stock  shots;  this  practice  is  likely  to  cause  trouble  if  both 
original  reversal  films  and  prints  are  used.  The  producer  and  editor 
should  familiarize  themselves  with  the  emulsion  position  and  set 
their  own  working  standards.  Recently  I  saw  an  original  16-mm 
Kodachrome  sent  in  for  printing.  The  photography  contained  film 
made  on  a  silent  stock  and  16-mm  sound  stock,  which  is  all  right. 
There  were  16-mm  sound  leaders  on  both  ends  of  the  photography. 
This  was  also  all  right,  except  that  the  leader  on  one  end  was  spliced 
with  the  sprocket-holes  on  one  side  and  the  other  leader  had  the 
sprocket-holes  on  the  other  side.  The  editor  said  he  did  not  know 
which  side  he  was  supposed  to  use  so  he  used  both  sides ! 

The  suggested  recommended  practice:  when  using  the  double  system,  shoot 
the  picture  on  stock  perforated  on  both  sides.  Follow  this  procedure  all  the  way 
through.  If  stock  shots  are  used,  they  should  be  on  this  type  of  stock  if  possible. 
If  sound  stock  must  be  used,  be  sure  it  can  be  printed.  (A  standard  16-mm 
reduction  sound-print  can  be  cut  into  an  original  reversal  film  with  emulsion 
positions  the  same  and  should  go  through  any  of  the  printers  being  used  today.) 

Original  pictures  and  sound-tracks  coming  into  a  laboratory  for 
printing  are  the  most  variable  things  imaginable.  We  have  our  own 


342 


L.  THOMPSON 


[J.  S.  M.  P.  E. 


Oct.,  1943]  DIRECT  16-Mn  PRODUCTION  343 

standards  for  attaching  leaders  to  original  film  for  printing,  and  we 
shall  be  glad  to  send  them  to  anyone  who  is  interested.  We  have  had 
some  difficulty  in  getting  people  to  follow  them  and  have  even  been 
told  that  they  are  not  correct,  but  they  have  been  checked  a  number 
of  times  and  we  are  certain  of  their  validity.  We  have  suggested  that 
identification  and  synchronizing  marks  be  placed  upon  both  ends  of  the 
photograph  and  sound-track  reels  because  all  laboratories  do  not 
print  from  the  same  end.  Since  16-mm  printers  are  not  standardized, 
this  is  probably  the  only  procedure  that  can  be  recommended.  Fig.  1 
shows  a  suggested  recommended  practice. 

The  standard  leader  developed  for  35-mm  film  is  used  by  some  pro- 
ducers for  their  16-mm  originals.  We  are  opposed  to  this  practice 
because  in  the  field  operators  will  often  project  the  numbers  on  the 
screen  at  the  beginning  of  the  picture.  For  good  presentation  plain, 
marked  leaders  should  be  spliced  to  each  new  reel. 

As  a  suggested  recommended  practice  a  leader  four  or  five  feet  in  length,  such 
as  the  reversal  laboratories  use  on  amateur  reversal  prints,  is  proposed. 

If  there  is  anything  more  unstandardized  than  leaders,  it  is  the 
light-change  punch.  We  frequently  receive  originals  having  two  or 
three  sets  of  light-change  punches,  and  as  a  rule  none  of  these  will 
work  on  our  printers. 

We  have  no  suggested  recommended  practice  for  this.  The  only  suggestion  we 
can  offer  is  to  set  up  some  sort  of  standard,  and  in  time  most  of  the  laboratories 
will  probably  conform  to  it.  It  will  also  give  printer  manufacturers  a  basis  upon 
which  to  work. 

While  it  is  probably  not  the  duty  of  the  Society  to  set  up  standards 
for  the  emulsions  to  be  used  for  certain  jobs,  there  are  probably 
many  who  are  trying  to  do  16-mm  production  for  the  first  time  who 
would  welcome  some  sort  of  suggestions.  Over  a  period  of  years  we 
have  worked  with  many  who  were  trying  to  make  their  own  pictures, 
and  there  have  been  times  when  they  failed  simply  because  they 
used  the  wrong  type  of  emulsion.  We  have  found  people  trying  to 
shoot  contrasty  titles  on  blue-base  negative  stock  instead  of  using  a 
high-contrast  positive  film. 

While  certain  types  of  16-mm  film  on  the  market  can  be  developed 
as  either  negative  or  reversal,  most  types  of  negative  film  will  not 
"reverse"  successfully.  Nevertheless  certain  persons  still  persist  in 
trying. 

For  several  years  the  emulsion  makers  have  been  selling  16-mm 


344  L.  THOMPSON  [j.  s.  M.  p.  E. 

sound-recording  film  that  is  definitely  superior  to  positive  film,  but  a 
few  persons  still  try  to  use  ordinary  positive  stock  and  others  wonder 
why  their  dupe  negatives  do  not  turn  out  well  when  they  try  to  make 
them  on  positive  film. 

In  suggesting  certain  emulsions  for  specific  purposes  it  should  be 
borne  in  mind  that  the  list  is  subject  to  change.  It  is  fairly  standard 
procedure  for  16-mm  producers  to  shoot  their  original  photography 
on  either  black-and-white  reversal  film  or  on  color-film.  (There  are 
some  cases  where  color-film  is  used  entirely,  even  when  black-and- 
white  prints  are  wanted.)  The  following  emulsions  are  suggested : 

Black-and-White  Photography 

Original. — Standard-brand  reversal  film  or  color-film.  The  brand  and  type 
must  be  decided  upon  by  the  individual.  (For  procedure  see  reference  2.} 

Titles. — High-contrast  positive  film  for  cheap  titles,  but  for  professional  titles 
reversal  film  with  the  proper  art  work. 

Work  Prints. — Reversal  prints  on  positive  film,  yellow-dyed  sound-recording 
stock  (perforated  on  both  sides),  or  reversal  duplicating  film.  The  positive  film 
is  cheaper,  and  will  usually  serve  the  purpose. 

Release  Prints. — Reversal  duplicates  made  on  reversal  duplicating  film  for  first 
prints,  or  for  only  a  few  prints.  Dupe  negatives  should  be  used  for  a  large  number 
of  prints  and  should  be  made  on  panchromatic  fine-grain  duplicating  negative. 
Positive  prints  from  duplicate  negatives  are  best  when  made  on  fine-grain  positive 
film. 

Color  Photography 

Original. — Standard-brand  reversal  color-film  such  as  Kodachrome  or  Ansco 
Color.  Mazda-light  type  for  Mazda  lights,  and  daylight-type  for  daylight. 
(Some  prefer  the  Mazda  type  with  filters  for  exteriors.) 

Work  Prints. — Same  as  for  work-prints  from  original  black-and-white  photogra- 
phy, unless  the  editor  feels  he  must  use  color  work-prints,  in  which  case  a  regular 
color  release-print  is  made. 

Release  Prints. — (a)  Color:  Made  on  Kodachrome  duplicating  film,  or  equiva- 
lent, (b)  Black-and-white:  Follow  same  procedure  as  with  black-and-white 
dupe  negatives.  If  black-and-white  reversal  prints  are  wanted  it  is  best  to  use  a 
duplicating  film  that  is  not  color-blind,  although  it  is  more  costly. 

Sound 

Original. — Use  a  16-mm  sound-recording  emulsion  made  especially  for  the  pur- 
pose. 

Prints  of  Sound  Only. — Fine  grained  positive  film. 

We  offer  the  above  as  recommended  practice  for  correct  16-mm  production, 
and  if  the  producer  will  follow  these  suggestions  he  can  not  go  far  wrong  as  16-mm 
production  is  done  at  the  present  time. 

There  have  been  a  number  of  direct  16-mm  productions  made 
where  no  work-print  was  used  during  the  editing  process,  but  as  more 


Oct.,  1943]  DIRECT  16-Mn  PRODUCTION  345 

persons  become  involved  in  the  production  of  a  picture,  the  more 
necessary  it  becomes  that  the  first  editing  be  done  with  work-prints. 
One  serious  difficulty  in  using  16-mm  work-prints  is  that  there  has 
been  no  standard  method  of  edge-numbering  originals  and  work- 
prints  so  that  the  two  can  be  easily  matched. 

For  several  years  the  Society  has  been  discussing  16-mm  edge- 
numbering,  and  a  Recommended  Practice  was  finally  set  up.  This 
is  all  well  and  good,  except  for  the  fact  that  edge-numbered  films  are 
available  only  on  special  order,  and  a  number  of  emulsions  are  on  the 
market  that  must  be  used  in  direct  16-mm  production  that  are  not 
available  with  edge-numbers  under  any  condition. 

Some  time  ago  I  recommended  to  the  Society  that  all  16-mm  re- 
versal and  sound-films  be  edge-numbered  if  the  system  were  to  work 
out  successfully  for  16-mm  production.  However,  because  of  certain 
manufacturing  difficulties  it  is  not  practicable  to  edge-number  all 
16-mm  reversal  film  because  there  is  no  need  for  edge-numbering 
most  amateur  films.  For  that  reason  I  am  now  going  to  change  my 
recommendation.  Since  it  seems  to  be  impossible  to  get  all  16-mm 
producers  to  place  special  orders  for  edge-numbered  film  and  use  no 
other  kind  of  stock,  it  is  recommended  that 

when  work-prints  are  made  of  the  originals,  the  original  photography  and  work- 
print  be  numbered  by  a  machine  as  is  done  in  35-mm  practice. 

The  work-prints  can  first  be  made,  then  the  edge-numbers  be  put 
on  the  work-print  to  synchronize  with  the  edge-numbering  on  the 
original  developed  photography.  These  numbers  can  be  printed  also 
on  the  sound-track.  The  producer  is  thus  relieved  of  the  necessity 
of  using  edge-numbered  film  for  his  originals.  Unfortunately  we 
know  of  no  one  at  the  present  time  who  can  offer  this  service,  but 
we  have  investigated  its  possibilities  and  believed  that  before  long 
such  a  service  will  be  offered. 

There  are  many  kinds  of  work-prints.  Some  have  used  regular 
black-and-white  reversal  prints;  others  have  had  full-color  prints 
made  from  their  color  photography;  and  some  work-prints  have 
been  made  as  negatives  after  they  have  been  printed  on  positive  film. 
Since  most  persons  do  not  want  to  pay  any  more  than  is  necessary  for 
work-prints,  we  have  found  that  work-prints  made  on  some  cheap 
emulsions  such  as  ordinary  positive  film,  and  then  reversed,  give 
very  satisfactory  results  for  most  purposes.  Work-prints  from  color- 
film  made  in  this  way  are  also  satisfactory. 


346  L.  THOMPSON  [j.  S.  M.  P.  E. 

We  therefore  suggest  the  following  recommended  practice:  Black-and-white 
work-prints  from  original  black-and-white  photography  or  color-film  to  be  made 
on  positive  film  and  reversal-processed  where  the  minimum  amount  is  to  be  spent. 
If  better-quality  work-prints  are  desired,  use  regular  reversal  prints  for  black-and- 
white  or  color  or  color-prints  for  color  photography. 

Many  who  are  making  direct  16-mm  pictures  for  the  first  time  do  not 
seem  to  realize  the  importance  of  securing  the  proper  density  for  their 
original  sound-tracks  or,  if  they  do,  they  seem  unable  to  give  the 
proper  exposure  to  their  film  in  order  to  realize  this  density.  The 
manufacturers  of  the  film  have,  in  most  cases,  suggested  proper 
densities  for  their  film,  but  there  are  far  too  many  cases  where  these 
recommendations  are  not  followed.  This  is  something  that  can  be 
made  a  recommended  practice,  but  each  producer  will  have  to  work 
out  his  own  standards.  Control  of  exposure  for  sound-tracks  must  be 
critically  and  carefully  checked. 

There  must  be  something  extremely  fascinating  about  the  manu- 
facture of  16-mm  reels,  because  it  seems  as  if  every  machine  shop  in 
the  country  has  put  some  sort  of  16-mm  reel  on  the  market.  After 
examining  some  of  these  reels,  we  wonder  whether  some  of  the  manu- 
facturers ever  saw  a  16-mm  reel  before.  A  few  years  ago  we  thought 
the  16-mm  reel  was  pretty  well  standardized  and  would  probably  be 
rather  hard  to  change.  However,  so  many  changes  have  been  made 
during  the  past  year  or  two  that  it  is  quite  appropriate  to  suggest 
standardization.  The  original  16-mm  reel  was  made  for  amateur 
use,  and  the  idea  of  using  a  round  hole  on  one  side  and  a  square  hole 
on  the  other  side  was  to  make  sure  the  reel  was  placed  properly  on  the 
spindle.  We  have  never  yet  seen  a  16-mm  professional  who  likes 
reels  of  this  type.  Editors  and  cutters  of  16-mm  film  find  them  es- 
pecially bad.  We  have  found  them  with  all  sorts  of  hub  sizes,  some  of 
which  have  been  made  so  small  that  they  will  not  work  properly  on 
certain  types  of  take-ups  at  the  beginning  of  the  film. 

We  suggest  that  16-mm  reels  be  standardized  with  square  holes  on  both  sides, 
and  that  a  certain  hub  diameter  be  chosen  and  adopted  as  standard. 

Sixteen-mm  editing  equipment  for  the  most  part  is  made  to  handle 
reels  instead  of  cores,  as  is  common  in  35-mm  practice.  Nearly  every- 
one who  has  done  much  work  with  16-mm  uses  these  reels  in  editing, 
and  most  16-mm  originals  received  in  laboratories  for  printing  come 
in  on  reels.  Furthermore,  it  is  much  safer  and  easier  to  handle  film 
on  reels. 


Oct.,  1943]  DIRECT  16-MM  PRODUCTION  347 

We  suggest,  therefore,  that  it  be  recommended  practice  to  handle  16-mm  film 
on  16-mm  reels. 

We  find  that  16-mm  film  sent  in  for  printing  comes  in  all  sorts  of 
lengths.  Different  laboratories  are  set  up  to  handle  different  lengths — 
some  100  feet,  others  400  feet,  up  to  2000-ft  rolls.  This  is  all  right 
except  there  should  be  a  stopping  point  somewhere,  and  some  sort  of 
standard  set  for  it.  It  is  obviously  impossible  to  get  raw  stock  to 
match  the  exact  footage  for  every  show,  and  this  becomes  somewhat 
of  a  headache  when  sound  is  to  be  printed. 

For  a  suggested  recommended  practice  we  suggest  that  original  picture  and 
sound-track  for  16-mm  be  edited  into  lengths  of  390  feet  so  they  may  be  printed 
on  standard  length  rolls  of  400  feet.  Leaders  may  bring  the  length  up  to  398  feet. 

It  probably  does  not  make  much  difference  in  the  final  results,  but 
we  feel  that  it  might  be  a  good  idea  to  standardize  the  direction  of 
editing  16-mm  film.  Some  persons  edit  from  right  to  left  and  others 
from  left  to  right.  This  is  partially  a  matter  of  taste  and  par- 
tially a  matter  of  equipment  and  the  introduction  of  16-mm  sound- 
tracks to  the  editing  procedure.  Certain  equipment  seems  to  work 
better  in  one  direction  than  in  the  other.  Reels  with  square  holes  on 
one  side  and  round  holes  on  the  other  call  for  editing  in  one  direction, 
and  reels  with  square  holes  on  both  sides  will  allow  the  editor  to  work 
in  either  direction.  The  splicer  that  is  probably  most  commonly 
used  for  16-mm  editing  is  the  Junior  Griswold  with  the  1/i6-inch  splice. 
When  using  this  on  original  sound-film  it  is  almost  necessary  to  edit 
from  left  to  right.  We  have  done  so  for  years  and  have  found  a  num- 
ber of  others  who  follow  this  procedure.  All  the  equipment  manu- 
facturers do  not  agree  and  we  suggest  that  some  practice  be  recom- 
mended in  order  that  all  editing  equipment  be  in  agreement. 

Producers  of  16-mm  pictures  should  standardize  their  techniques 
of  performing  certain  operations  and  then  adhere  to  their  standards. 
We  have  received  commercial  pictures  for  printing  that  contained 
splices  made  on  three  or  four  different  kinds  of  splicers.  Such  little 
things  can  make  a  show  look  like  the  work  of  an  amateur  instead  of 
the  work  of  a  professional. 

There  is  a  great  deal  of  work  to  be  done  in  standardizing  16-mm 
production  methods.  This  paper  has  listed  only  a  few  of  the  problems. 
It  is  hoped  that  other  16-mm  producers  will  submit  their  suggestions 
and  that  eventually  some  of  the  suggested  recommended  practices 
will  become  standards. 


348  L.  THOMPSON  [J.  S.  M.  p.  E 

REFERENCES 

1  OFFENHAUSER,  W.  H. :     "A  Review  of  the  Question  of  16-Mm  Emulsion  Posi- 
tion," /.  Soc.  Mot.  Pict.  Eng.,  XXXIX  (Aug.,  1942),  p.  123. 

2  THOMPSON,  L. :     "Some  Equipment  Problems  of  the  Direct  16-Mm  Producer," 
/.  Soc.  Mot.  Pict.  Eng.,  XLI  (July,  1943),  p.  101. 

DISCUSSION 

MR.  OFFENHAUSER:  Mr.  Thompson's  paper  contains  much  food  for  thought 
and  raises  a  number  of  important  related  questions.  Let  us  consider  his  recom- 
mendation of  the  Griswold  Jr.  splicer  with  a  Vie-inch  splice. 

For  more  than  two  years  all  splices  made  in  original  films  in  our  laboratory 
have  been  made  with  a  hot-splice  type  Bell  &  Howell  laboratory  splicer,  con- 
verted to  make  a  0.070-inch  straight  splice.  The  splicer  is  accurately  adjusted 
to  produce  a  0.010-inch  overlap  on  either  side  of  the  sprocket-hole.  On  the  right 
side  of  the  splicer,  an  extension  guide  has  been  added  that  is  quite  long  relative 
to  the  width  of  the  film.  This  guide,  which  is  chromium  plated,  makes  it  im- 
possible to  "skew"  the  film  on  the  right  side  of  the  splicer  with  respect  to  the 
film  on  the  left  side  of  the  splicer;  the  alignment  of  a  splice  is  almost  as  good  as 
that  of  a  continuous  piece  of  film. 

The  scraper  for  the  splicer  is  very  important ;  it  is  accurately  adjusted  for  depth 
of  cut  and  is  kept  honed  by  regular  day-to-day  maintenance.  Splices  are  checked 
under  a  microscope  regularly  every  day  to  make  certain  that  nothing  was  damaged 
in  the  previous  day's  operations. 

To  those  who  inspect  splices  under  a  microscope  (and  for  commercial  16-mm 
film,  all  of  us  should  do  so),  the  use  of  a  Griswold  Jr.  splicer  seems  really  crude. 
While  it  is  probably  one  of  the  best,  if  not  the  best,  hand-type  splicer  on  the 
market,  its  shortcomings  are  such  that  our  laboratory  discarded  it  over  two  years 
ago.  These  shortcomings  are: 

(1)  It  does  not  produce  a  "hot"  splice. 

(2)  It  can  not  be  adjusted  to  provide  equal  overlap  on  either  side  of  the 
sprocket-hole. 

(3)  When  adjusted,  it  does  not  retain  its  adjustment. 

(4)  It  is  not  readily  readjusted.     (Readjustment  is  required  periodically  for 
every  splicer.) 

The  characteristics  of  a  splicer  alone,  however,  do  not  tell  the  whole  story; 
the  question  of  the  skill  with  which  the  splicer  is  used  is  so  often  a  controlling 
factor  that  the  mere  possession  of  the  best  splicer  is  no  assurance  of  the  best  results. 

I  am  definitely  not  in  favor  of  the  Griswold  Jr.  splicer.  Nothing  less  than  the 
modified  Bell  &  Howell  laboratory  splicer  is  suitable  for  large-scale  high-quality 
work;  an  operator  can  make  50  per  cent  more  splices  per  day  with  far  less  effort 
and  fatigue.  Every  splice  made  should  be  a  good  one — and,  with  proper  care, 
will  be. 

Very  little  maintenance  attention  is  needed  for  the  Bell  &  Howell  splicer  pro- 
vided that  those  who  use  it  are  fairly  skillful;  however,  a  careless  or  unskilled 
person  can,  in  a  matter  of  seconds,  put  the  splicer  out  of  commission  for  a  half- 
hour  or  longer.  Adequate  training  of  a  careful  person  requires  but  a  few  hours 
if  that  person  has  the  necessary  aptitude. 


Oct.,  1943]  DIRECT  16-MM  PRODUCTION  349 

What  has  just  been  said  about  splicers  may  be  applied  to  any  class  of  machinery. 
To  use  any  machine  successfully  requires  ever- vigilant  inspection  to  assure  that 
the  machine  (and  the  operator)  continues  to  fulfill  its  purpose.  This  inspection 
not  only  cures  difficulties  when  and  as  they  arise,  but  also  has  as  its  most  important 
function  the  anticipating  of  difficulties  before  they  have  grown  to  significant  magnitude. 

In  a  broader  sense,  this  identical  line  of  reasoning  has  already  been  successfully 
applied  to  armament  production.  Before  a  contractor  who  is  to  manufacture 
materiel  receives  the  "green  light,"  he  must  prove  his  ability  to  produce  the 
desired  product  with  the  required  quality — and  to  prove  also  that  he  can  con- 
sistently maintain  that  quality  in  mass  production.  It  is  common  practice  that 
one  or  more  of  the  successful  samples  is  referred  to  when  checking  the  product 
being  currently  produced.  It  has  been  the  unswerving  adherence  to  this  policy 
that  has  made  possible  the  manufacture  of  superior  war  supplies  by  manufac- 
turers of  refrigerators,  automobiles,  elevators,  and  a  host  of  other  peacetime 
products. 

It  would  seem  that  this  principle  which  has  been  so  successful  in  armament 
procurement  should  be  equally  successful  in  the  procurement  of  prints  of  our 
training  films.  Our  laboratory  industry  has  a  tremendous  advantage  over  the 
automobile  industry  and  the  refrigerator  industry  in  the  solution  of  the  problem ; 
the  product  of  the  film  laboratory  is  not  sensibly  different  in  wartime  from  what 
it  is  in  peacetime.  The  advantage  should  be  reflected  in  the  superiority  of  the 
product  manufactured. 

War  has  demanded  a  steady  lifting  of  the  quality  level  of  all  armament  materiel ; 
it  should  likewise  demand  a  steady  lifting  of  the  quality  level  of  all  16-mm  prints 
of  training  films  manufactured.  This  improvement  can  be  readily  obtained  if 
our  Government  contracts  will  stress  the  product  to  be  produced;  and  specify 
that  product  in  measurable  physical  terms.  The  possession  of  a  good  bank 
statement  and  credit  references  together  with  particular  facilities  and  special 
kinds  of  machinery  such  as  Cinex  testers  and  the  like  has  no  effect  whatever  upon 
the  quality  of  the  desired  products:  prints  of  training  films. 

There  is  dire  need  for  rigid  inspection  of  prints  of  training  films  and  for  quality 
specifications  that  will  be  sure  to  reject  all  defective  prints.  The  all-too-common 
philosophy  of  "it  costs  too  much  to  reject  defective  prints"  and  "it  is  good  enough, 
anyhow"  aggravates  an  already  serious  situation.  We  can  be  thankful  that  this 
sort  of  delusion  was  not  shared  by  those  who  supplied  the  guns  and  bullets  to 
the  men  on  Guadalcanal. 

Ever- vigilant  inspection  can  do  as  much  to  improve  the  quality  of  16-mm 
prints  as  it  does  to  improve  the  quality  of  our  ordnance.  Let's  give  it  a  chance 
by  specifying  the  product,  and  not  the  tools  that  someone  happens  to  use  to  make  the 
product.  Let  us  have  rigid  inspection  under  product  specifications,  and  enjoy 
the  benefits  of  improved  quality  and  lower  costs  resulting  therefrom. 

MR.  TUTTLE:  There  has  been  and  still  is  considerable  confusion  on  the  part 
of  many  users  of  Kodachrome  film  on  the  subject  of  the  type  of  film  to  use  with 
different  light  sources  available. 

The  daylight  type  of  Kodachrome  film  is  suitably  color-balanced  so  that  it 
matches  the  color  temperature  of  sunlight  and  blue  sky  which  normally  prevails 
in  outdoor  photographic  work.  The  average  mixture  of  sunlight  and  blue  sky 
has  a  color  temperature  of  about  6100°  Kelvin.  Therefore,  the  daylight  type  of 


350  L.  THOMPSON 

Kodachrome  film  is  suitably  color-balanced  to  match  it.  The  Type  A  or  arti- 
ficial-light Kodachrome  film  is  suitably  color-balanced  to  match  the  photoflood 
type  of  illumination  which  has  a  color  temperature  of  approximately  3450° 
Kelvin  when  used  on  a  120-volt  line. 

Filters  were  made  available  for  these  two  films  principally  to  permit  the  use  of 
short  unexposed  pieces  of  film,  remaining  in  the  camera,  in  different  types  of 
illumination  than  originally  specified.  Rather  than  discard  the  film  when  the 
illumination  is  changed,  it  may  be  exposed  by  using  the  proper  filter.  For  this 
purpose  the  No.  80  filter,  which  is  light  blue  in  color,  was  made  available  for  use 
on  the  camera  lens  when  daylight-type  Kodachrome  film  is  to  be  used  indoors 
with  photoflood  illumination.  The  No.  85  or  orange-colored  filter  was  made 
available  for  use  with  the  Type  A  film  in  using  the  short  lengths  of  film  out-of- 
doors.  It  is  not  the  intention  of  the  manufacturers  of  Kodachrome  film  that 
either  film  should  be  used  as  an  all-purpose  film  with  filters  hi  opposite  types  of 
lighting  for  which  the  film  was  manufactured. 

For  the  most  satisfactory  results  on  Kodachrome  film  the  daylight  type  of 
film  should  be  used  when  pictures  are  made  in  the  normal  mixture  of  sunlight 
and  blue  sky;  Type  A  Kodachrome  film  should  be  used  with  the  photoflood  type 
of  lamp  on  a  line  of  proper  voltage. 

There  are  many  factors  relating  to  the  use  of  filters  with  various  light-sources 
which  enter  into  such  a  discussion,  and  the  technical  reasons  for  not  using  filters, 
unless  necessary,  are  many  and  require  a  much  lengthier  technical  discussion 
than  is  permissible  here.  However,  it  is  sufficient  to  say  that  if  daylight  type 
of  Kodachrome  film  is  used  in  sunlight  and  the  Type  A  Kodachrome  film  is  used 
with  either  the  No.  1  or  No.  2  photoflood  lamps;  and  if  a  color-temperature  meter 
is  used  to  check  the  color  quality  of  the  light-source  to  make  certain  that  it  is 
approximately  3450  °  Kelvin,  the  best  possible  color  rendition  will  be  obtained  on 
each  type  of  film. 


RESISTANCE  OF  GLASS  TO  THERMAL  SHOCK5 
CHARLES  D.  OUGHTON** 


Summary. — The  resistance  of  glass  to  thermal  shock  may  be  increased  considerably 
by  tempering  which  is  the  controlled  introduction  of  strain.  Tempering  and  annealing 
represent  opposite  extremes  in  heat  treatment.  Annealing  removes  strain  by  slow 
cooling  while  tempering  introduces  strain  by  rapid  cooling.  Glass  fractures  originate 
in  regions  of  tension.  When  hot  glass  is  subjected  to  a  cold  medium,  a  thermal 
gradient  is  introduced  and  the  resulting  strain  distribution  places  the  surface  in  a 
state  of  tension.  If  the  tension  exceeds  the  tensile  strength  of  the  glass  a  fracture  will 
occur.  Condenser  lenses  of  projection  machines  are  often  subjected  to  thermal  shock 
of  this  type.  Tempering  the  glass  places  the  surfaces  under  compression.  A  much 
greater  thermal  shock  may  then  be  applied  without  causing  fracture,  because  sufficient 
stress  must  be  introduced  to  completely  neutralize  the  compression  before  the  surface 
can  go  into  tension  and  fail. 

The  breakage  of  reflectors,  condensers,  and  occasionally  projection 
lenses  from  heat  is  a  common  occurrence  in  lanterns  with  high  in- 
tensity arcs.  This  is  in  accord  with  a  number  of  everyday  ex- 
periences, such  as  hot  glass  cracking  when  placed  in  cold  water  or 
touched  to  a  cold  object.  Such  breakage  is  a  result  of  the  tremendous 
shock  to  which  glass  may  be  subjected  by  even  a  small  change  in 
temperature.  When  costly  optical  glass  is  involved  the  phenomenon 
requires  investigation  from  the  practical  viewpoint  of  how  to  make 
glass  resistant  to  thermal  shock. 

Several  general  observations  concerning  glass  should  be  noted. 
Glass  expands  when  heated.  The  fractional  amount  by  which  it 
expands  per  degree  of  temperature  rise  is  known  as  its  coefficient 
of  expansion.  The  coefficient  varies  with  the  composition  of  the 
glass;  for  example,  glass  having  a  relatively  low  percentage  of  silica 
has  a  high  coefficient  of  expansion,  while  glass  with  a  high  silica 
content  has  a  low  coefficient  of  expansion.  If  one  section  of  a  plate 
of  glass  is  raised  to  a  relatively  higher  temperature  than  that  of  the 
surrounding  or  adjacent  glass,  the  heated  portion  expands.  The 

*  Presented  at  the  1943  Spring  Meeting  at  New  York. 
**  Scientific  Bureau,  Bausch  &  Lomb  Optical  Co.,  Rochester,  N.  Y. 

351 


352  C.  D.  OUGHTON  [j.  s.  M.  P.  E. 

thermal  gradient  from  the  heated  section  to  the  surrounding  glass 
with  a  corresponding  change  in  dimensions  introduces  stress.  When 
stress  exceeds  the  tensile  strength  of  the  glass  a  fracture  occurs. 
Glass  having  a  low  coefficient  of  expansion  will  permit  a  greater  tem- 
perature gradient  for  a  given  amount  of  stress  than  will  glass  with  a 
high  coefficient  of  expansion. 

Stress  caused  by  the  thermal  gradient  produces  strain  in  the  glass. 
Two  conditions  of  strain  exist  that  are  of  interest  in  this  instance 
— tension  and  compression.  Bending  a  bar  of  glass  places  tensional 
strain  on  the  side  being  stretched  and  compressional  strain  on  the  side 
being  squeezed.  A  neutral  layer  of  no  strain  will  pass  through  the 
central  region  of  the  bar.  Glass  fractures  originate  in  a  region  of 
tension.  Considerable  tension  may  be  easily  introduced  where  a 
flaw  or  weakness  is  present  in  the  glass.  Flaws  are  often  micro- 
scopic and  unnoticeable.  It  is  reasonable  to  assume  that  surface 
flaws  should  weaken  glass  more  than  internal  flaws  and,  correspond- 
ingly, more  fractures  originate  at  the  surface. 

With  these  considerations  in  mind,  two  solutions  are  available 
for  increasing  the  resistance  of  glass  to  thermal  shock :  first,  the  glass 
may  be  given  a  high  silica  content  with  a  correspondingly  low  co- 
efficient of  expansion;  and,  secondly,  the  glass  may  be  tempered  to 
place  the  outer  region  or  surface  layers  under  compressional  strain, 
thus  preventing  tension  from  reaching  the  surface  flaws.  This  latter 
approach  presents  rather  interesting  results. 

Tempering  involves  a  heat  treatment  that  is  the  opposite  extreme 
to  annealing.  Annealing  consists  of  slow  cooling  to  remove  strain. 
Tempering  introduces  strain  by  rapid  cooling.  In  both  instances 
the  glass  is  heated  to  a  temperature  slightly  below  the  softening 
temperature.  In  this  temperature  range  the  stress  is  completely 
removed  from  the  glass.  By  cooling  slowly  to  room  temperature, 
over  a  period  of  hours,  the  glass  assumes  an  unstrained  or  annealed 
condition.  By  cooling  the  glass  to  room  temperature  in  an  interval 
of  a  few  minutes,  in  a  stream  of  air  or  by  immersion  in  a  liquid  bath, 
the  glass  is  placed  in  a  strained  condition  and  is  said  to  be  tempered. 

If  tempered  properly  such  glass  is  capable  of  resisting  considerably 
more  thermal  and  physical  shock  than  annealed  glass.  It  is  placed 
on  the  market  under  a  variety  of  trade  names  and  is  used  in  laboratory 
glassware,  safety  goggles,  car  windows,  etc.,  where  physical  and 
thermal  shocks  are  likely  to  occur. 

An  examination  of  the  strain  conditions  in  tempered  glass  will 


Oct.,  1943  j       RESISTANCE  OF  GLASS  TO  THERMAL  SHOCK  353 

indicate,  in  general,  how  the  glass  is  made  resistant  to  thermal  shock. 
To  explain  in  detail  the  origin  and  conditions  of  strain  in  tempered 
glass  is  beyond  the  scope  of  this  paper.  It  will  be  sufficient  to  state 
that  in  tempered  glass  the  entire  surface  region  is  in  a  state  of  com- 
pressional  strain ;  the  center  is  under  tension,  and  between  the  center 
and  the  surface  there  is  a  neutral  zone  of  isotropic  strain.  When  hot 
glass  is  suddenly  cooled  the  outer  region  solidifies  over  an  expanded 
hot  central  region.  As  the  central  region  is  cooled  to  room  tem- 
perature by  the  cold  surface,  it  can  not  contract  to  its  normal  dimen- 
sions because  of  the  solidified  but  expanded  outer  surface  of  the  glass. 
This  leaves  the  center  under  tension. 

Remembering  that  in  untempered  glass  fractures  originate  at 
surface  flaws  when  the  tension  around  the  flaw  exceeds  the  tensile 
strength  of  the  glass,  it  is  apparent  that  the  state  of  strain  introduced 
into  the  glass  by  tempering  should  increase  its  resistance  to  thermal 
shock.  Before  the  tensional  stress  at  the  surface  can  exceed  the 
tensile  strength  of  the  glass  after  tempering,  it  must  counteract  the 
compressional  stress  that  has  been  introduced  over  the  complete 
surface.  Thus,  a  more  severe  shock  is  required  to  fracture  tempered 
glass  than  untempered  glass.  When  tempered  glass  does  fracture 
indications  show  that  the  break  often  originates  in  the  central  ten- 
sional region. 

Glass  is  most  likely  to  break  when  it  is  plunged  suddenly  from  a  hot 
medium  into  a  cold  medium.  In  heating  untempered  glass  from  room 
temperature  to  a  much  higher  temperature  (cold  to  hot  thermal 
shock),  the  surface  is  placed  in  a  state  of  temporary  compressional 
strain.  Thus  there  is  little  chance  of  a  break  originating  under  this 
condition.  But,  when  glass  is  cooled  rapidly  from  a  high  temperature 
to  a  low  temperature,  the  surface  is  placed  in  a  state  of  temporary 
tensional  strain  and  a  fracture  is  likely  to  occur.  Condenser  lenses 
of  projection  machines  are  almost  constantly  subjected  to  thermal 
shock  of  this  latter  type.  Their  fracture  is  a  familiar  and  frequent 
occurrence,  and  therefore  the  lenses  serve  as  excellent  examples  for 
the  application  of  the  above  principles. 

Properly  annealed  condenser  lenses  of  the  highest  illuminating 
efficiency,  even  when  made  of  the  best  thermal  shock-resistant 
glass,  have  a  very  brief  life  when  used  with  high-intensity  arcs.  This 
is  due  to  the  tremendous  thermal  shock  to  which  the  lenses  are  sub- 
jected. Only  a  few  inches  from  the  piano  side  of  the  condenser  is  a 
carbon  arc  carrying,  perhaps,  175  amperes  which  acts  as  a  source  of 


354 


C.  D.  OUGHTON 


[J.  S.  M.  P.  E. 


heat.  While  this  side  of  the  lens  is  held  at  a  high  temperature,  the 
opposite  side  radiates  the  heat  and  has  a  considerably  lower  tem- 
perature. The  result  is  a  thermal  gradient  that  may  cause  fracture. 
Ordinary  optical  crown  glass  would  last  only  a  few  minutes  under 
these  conditions.  Even  well-annealed  Pyrex  glass  with  a  much 
lower  coefficient  of  expansion  fails  to  withstand  such  thermal  shock 
for  a  reasonable  length  of  time.  A  solution  to  the  problem  is  found 
in  fused  silica,  often  referred  to  as  fused  quartz,  with  Vith  the  co- 
efficient of  expansion  of  Pyrex.  Fused  silica  is  expensive  to  prepare, 
but  serves  satisfactorily  until  the  surface  becomes  pitted  from  the 
arc. 


(a)  0) 

FIG.  1.  Polariscope  strain  patterns  in  condenser  lenses  (a)  before  and  (&) 
after  use  with  source  of  heat  on  piano  side.  The  increased  number  of  bands 
in  (&)  indicates  that  the  compressional  strain  on  the  piano  side  has  been 
partially  removed. 


A  lens  made  of  glass  having  a  low  coefficient  of  expansion,  such  as 
Pyrex,  will  also  last  until  the  surface  becomes  pitted  if  it  is  tempered 
properly.  However,  the  life  of  a  tempered  lens  is  limited  by  the 
temperature  to  which  the  surface  near  the  arc  is  heated.  When 
used  with  a  high-intensity  arc  the  tempered  lenses  will  eventually 
break.  A  comparison  of  the  strain  pattern  in  a  condenser  lens  after 
tempering  and  again  after  50  hours'  use  in  a  motion  picture  pro- 
jector, using  a  175-ampere  arc,  reveals  a  rather  startling  phenomenon: 
the  lens  appears  to  have  more  strain  after  use  than  before. 
Fig.  1  illustrates  this  difference:  (a)  is  a  photograph  of  the  strain 


Oct.,  1943]      RESISTANCE  OF  GLASS  TO  THERMAL  SHOCK 


355 


pattern  of  a  tempered  condenser  lens  in  plane  polarized  light  before 
being  subjected  to  the  treatment  described  above;  (b)  shows  the  lens 
after  use.  The  additional  dark  bands  indicate  the  change  in  the 


f 


FIG.  2.  (a)  Polariscope  strain  pattern  in  a  glass  strip 
tempered  symmetrically  from  top  and  bottom  with  air. 

(&),  (c),  and  (d).  The  same  strip  after  successively  in- 
creasing periods  of  heat  application  to  the  lower  surface. 
The  arrows  indicate  the  neutral  band  of  zero  resultant  stress. 
The  outside  of  the  glass  is  under  resultant  compressional 
strain  and  the  inside  under  resultant  tensional  strain.  The 
decrease  in  the  number  of  neutral  bands  between  the  neutral 
layer  and  the  lower  surface  shows  that  the  heat  treatment 
has  progressively  relieved  the  compressional  stresses  in  this 
region. 


amount  of  resultant  strain.  From  the  analysis  of  the  method  of 
introducing  strain  into  glass  it  may  be  concluded  that  no  strain  has 
been  added,  because  the  glass  temperature  did  not  reach  the  annealing 


356  C.  D.  OUGHTON  [j.  s.  M.  p.  E. 

range  and  it  received  a  gradual  chilling  in  cooling  to  normal,  whereas 
it  originally  received  a  severe  chilling. 

The  solution  to  this  problem  is  found  in  the  manner  by  which  the 
lens  is  heated  in  the  projector.  The  piano  side  of  the  condenser  lens 
is  usually  placed  only  a  few  inches  from  the  carbon  arc  source. 
Carbon  arcs  drawing  a  high  current  act  as  a  source  of  con- 
siderable heat  that  raises  the  temperature  of  the  piano  side  of  the 
condenser  thus  decreasing  the  viscosity  of  the  glass  and  permitting 
the  gradual  release  of  the  surface  layers  of  strain.  This  is  shown 
in  Fig.  2.  A  strip  of  glass  4  in.  long,  3/4  in.  wide  and  y2  in.  thick  was 
air  tempered.  Fig.  2  (a)  shows  the  strain  pattern  in  the  strip  as  a 
result  of  cooling  uniformly  on  the  upper  and  lower  sides.  Con- 
siderable heat  was  then  applied  to  the  lower  side  of  strip  (a) .  Fig.  2 
(b),  (c),  and  (d)  show  the  gradual  release  of  strain  as  the  heat  was 
applied  for  successively  increasing  lengths  of  time.  The  arrow 
marks  the  neutral  line  of  zero  resultant  stress.  The  decrease  in  the 
number  of  dark  bands  between  the  neutral  line  and  the  surface  gives 
a  measure  of  the  decrease  in  the  compressional  strain  on  the  surface 
of  the  glass.  Considerably  more  strain  was  released  on  the  side 
heated  owing  to  the  lower  viscosity  of  the  glass  in  that  region.  Be- 
cause the  temperature  in  a  condenser  lens  varies  from  a  high  value 
on  the  piano  side  to  a  low  value  on  the  convex  side,  more  strain  should 
be  released  on  the  piano  side.  The  center  and  convex  side  of  the 
lens  tend  to  remain  in  tensional  and  compressional  states  of  strain 
as  limited  by  the  viscosity  of  the  glass  which  will  vary  according  to 
the  heat  distribution.  The  strain  pattern  in  the  lens  following  ex- 
posure to  a  high  temperature  for  some  time  gives  indications  of  con- 
siderably more  strain.  Previously,  the  strain  viewed  in  the  polar  i- 
scope  was  made  up  of  compression  on  the  convex  side,  minus  tension 
in  the  central  region,  plus  compression  on  the  piano  surface  which, 
in  the  usual  methods  of  tempering  thick  lenses,  will  add  up  to  re- 
sultant tension.  This  tension  is  indicated  in  the  polariscope  by  a 
series  of  colored  bands.  After  use  the  strain  pattern  is  made  up  of 
compression  on  the  convex  side,  minus  tension  in  the  central  region, 
plus  less  compression  than  previously  on  the  piano  side.  This  gives 
a  greater  resultant  tension  which  is  indicated  in  the  lens  by  an  in- 
crease in  the  number  of  colored  bands  (Fig.  1).  Actually,  there  is 
less  strain  in  the  lens,  and  also  a  less  effective  distribution  of  the  re- 
maining strain. 

Over  a  period  of  time  the  compressional  strain  on  the  piano  side 


Oct.,  1943]       RESISTANCE  OF  GLASS  TO  THERMAL  SHOCK  357 

will  be  released  sufficiently  to  permit  the  surface  flaws  to  enter  a 
state  of  tension  and  cause  a  fracture.  To  counteract  this  release 
of  strain  special  tempering  techniques  have  been  and  are  being  de- 
veloped to  place  a  thicker  layer  of  compression  on  the  glass  surface. 
Although  tempered  glass  will  not  endure  indefinitely  under  severe 
thermal  shock,  tempering  must  be  considered  as  a  useful  method 
of  increasing  the  resistance  of  glass  to  thermal  shock.  One  of  the 
best  examples  of  its  usefulness  is  found  in  condenser  lenses.  Whereas 
annealed  condensers  under  severe  thermal  shock  in  motion  picture 
projectors  will  last  only  a  few  hours,  the  tempered  condensers  will 
last  until  the  surface  becomes  pitted. 


CURRENT  LITERATURE  OF  INTEREST  TO  THE  MOTION  PICTURE 

ENGINEER 


The  editors  present  for  convenient  reference  a  list  of  articles  dealing  -with  subjzcts 
cognate  to  motion  picture  engineering  published  in  a  number  of  selected  journals. 
Photostatic  or  microfilm  copies  of  articles  in  magazines  that  are  available  may  be 
obtained  from  the  Library  of  Congress,  Washington,  D.  C.,  or  from  the  New  York 
Public  Library,  New  York,  N.  Y.,  at  prevailing  rates. 


American  Cinematographer 

24  (Mar.,  1943),  No.  3 

Shooting  Action  Movies  in  the  African  Desert  (p.  86) 
"Special-Effects"  and  Wartime  Production  (p.  89) 
Direct  16-Mm  vs.  35-Mm  for  Training  Film  Production 

(p.  91) 

A  "Model  EE"  Grows  Up  (p.  96) 
Professionalizing  the  Bolex  (p.  98) 
Practical  Pointers  on  16-Mm  Sound  Projection  (p.  102) 

24  (May,  1943),  No.  5 
Filming  Desert  Victory  (p.  167) 

Hollywood  Greets  Four  Soviet  War  Camera-Aces  (p.  168) 
Exposure  Control  in  Aerial  Photography  (p.  170) 

24  (June,  1943),  No.  6 
"Cheating"  on  Camera- Angles  (p.  217) 
Care  and  Operation  of  16-Mm  Sound  Projectors  (p.  218) 
More  about  "Strobo-Sync"  (p.  222) 

24  (July,  1943),  No.  7 
Screen  Tests  Aren't  Necessary!  (p.  249) 
The  Rhapsodic  Technique  (p.  250) 
Hollywood's  Own  War  Plants  (p.  252) 


O.    H.    BORRADAILE 

B.  HASKIN 
W.  A.  PALMER 

P.  A.  JACOBSON 
W.  STULL 
J.  W.  BOYLE 

D.  MACDONALD 

W.  STULL 

D.  W.  NORWOOD 

R.  MATE 

D.  L.  CONWAY 
S.  JEPSON 

C.  R.  ROGERS 

E.  S.  ROBERTS 
W.  STULL 


British  Kinematograph  Society,  Journal 

6  (Apr.,  1943),  No.  2 
Acoustics  in  the  Motion  Picture  Theater  and  Studio        N.  FLEMING 

(p.  48) 
A  35-Mm  Film  Pitch  Measuring  Instrument  (p.  63)  L.  J.  WHEELER 


Communications 

23  (May,  1943),  No.  5 
High-Fidelity  Systems,  Pt.  II  (p.  24) 
358 


A.  J.  EBEL 


CURRENT  LITERATURE 


359 


Educational  Screen 

22  (May,  1943),  No.  5 
Motion  Pictures— Not  for  Theatres,  Pt.  47  (p.  170) 

22  (June,  1943),  No.  6 
Motion  Pictures — Not  for  Theatres,  Pt.  48  (p.  206) 

Electronics 

16  (Mar.,  1943),  No.  3 
Pictures  by  Wire  and  Radio  (p.  112) 

Sound  Recording  Depends  upon  Electronics  (p.  114) 

Institute  of  Radio  Engineers,  Proceedings 

31  (Mar.,  1943),  No.  3 

The  Focusing  View-Finder  Problem  in  Television  Cam- 
eras (p.  100) 
Mercury  Lighting  for  Television  Studios  (p.  106) 

International  Projectionist 

18  (Feb.,  1943),  No.  2 

Analysis  of  a  Bridging  Amplifier,  Pt.  IV  (p.  7) 
Sound  and  Projection  Equipment  in  War  Department 

Theatres,  Pt.  I  (p.  9) 
Review  of  Projection  Fundamentals,  Pt.  VI  (p.  16) 

18  (Mar.,  1943),  No.  3 

Sound  and  Projection  Equipment  in  War  Department 
Theatres,  Pt.  II  (p.  16) 

18  (Apr.,  1943),  No.  4 

Practical  Pointers  on  16-Mm  Sound  Projection  (p.  7) 
Two  Resistance-Coupled  Voltage  Amplifiers  (p.  9) 
Peacetime  Planning  Means  Wartime  Projection  Room 
Efficiency  (p.  18) 

18  (May,  1943),  No.  5 

A  Modern  Inverse  Feedback  Amplifier  (p.  7) 
I.  P.  Contestants  Tackle  Crackling  and  Popping  Noises 
in  Sound  Systems  (p.  10) 

18  (June,  1943),  No.  6 

16-  vs.  35-Mm  Projection  in  Army  Training  Camps  (p.  7) 
Technical  Analysis  of  a  Sound  System  for  Small  Theatres 
(P- 9) 

18  (July,  1943),  No.  7 
Quality  Essential  in  P.  A.  Systems  (p.  7) 
Unusual   Effects   Produced   with  Discarded  Equipment 

(p.  12) 

A  Complete  Study  on  the  Prevention  of  Film  Damage 
(p.  16) 

Motion  Picture  Herald 

151  (Apr.  24,  1943),  No.  4 
16-Mm  Field  Expanding  to  Big  Business  Status  (p.  15) 


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JOURNAL  OF  THE  SOCIETY  OF 
MOTION   PICTURE   ENGINEERS 

VOLUME  XLI  •         •          •     NOVEMBER,  1943 

CONTENTS 

PAGE 
A  Motion  Picture  Arc-Lighting  Generator  Filter 

B.  F.  MILLER     367 
Notes  on  the  Application  of  Fine-Grain  Film  to  16-Mm 

Motion  Pictures  W.  H.  OFFENHAUSER,  JR.     374 

Planning  for  16-Mm  Production  R.  C.  HOLSLAG     389 

Precision  Recording  Instrument  for  Measuring  Film 

Width  S.  C.  CORONITI  AND  H.  S.  BALDWIN    395 

Conservation  of  Photographic  Chemicals      A.  HAINES    409 
Maps  on  Microfilm — Some  Factors  Affecting  Resolu- 
tion M.  BRUNO    412 
Sensible  Use  of  Refrigerants  under  the  Emergency 
Now  Confronting  the  Industry 

A.  C.  BUENSOD  AND  R.  W.  WATERFILL   426 

Film  Conservation  Methods — -A  Symposium :  432 

Film  Conservation  Methods  at  Universal  Studios 

G.  J.  DEMoss    434 
Film  Conservation  Methods  at  Republic  Studios 

D.  J.  BLOOMBERG  AND  J.  STRANSKY    437 
Film  Conservation  Methods  at  RKO  Studios 

P.  E.  BRIGANDI    442 
Film  Conservation  Methods  at  Columbia  Studios 

S.  J.  TWINING    444 
Film  Conservation  Methods  at  Paramount  Studios 

I.  M.  CHAMBERS    449 
Film   Conservation   Methods   at  Samuel   Goldwyn 

Studios  D.  A.  NEWELL    455 

Film  Conservation  Methods  at  Walt  Disney  Pro- 
ductions C.  O.  SLYFIELD    457 
Film  Conservation  Methods  at  Warner  Bros.  Studios 

G.  M.  BEST    459 
(The  Society  is  not  responsible  for  statements  of  authors.) 


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ARTHUR  C.  DOWNES,  Chairman 

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**Term  expires  December  31,  1944. 


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Picture  Engineers,  Inc. 


A  MOTION  PICTURE  ARC-LIGHTING  GENERATOR  FILTER 


B.  F.  MILLER^ 


Summary. — The  general  means  heretofore  employed  to  reduce  the  commutator 
noises  emitted  by  arc  lamps  operated  from  direct  current  generator  sets  is  outlined,  and 
the  deficiencies  of  such  equipment  are  noted.  The  design  of  an  electrical  filter  unit, 
which  is  extremely  compact  as  compared  to  previously  employed  equipment  and  which 
is  capable  of  handling  the  full  load  output  of  studio  stage-lighting  generators,  is 
described.  This  filter  completely  suppresses  all  arc-lamp  noises  resulting  from 
generator  commutator  ripple,  may  be  permanently  associated  with  any  studio  genera- 
tor set,  eliminates  the  need  for  repeated  installations  of  large  numbers  of  choke  coils 
on  the  set,  and  requires  no  servicing.  The  unit  is  capable  of  withstanding  current 
overloads  in  excess  of  100  per  cent  indefinitely. 


The  "whistle"  present  in  arc  lamps  owing  to  the  commutator  ripple 
of  the  power  supply  generators  has  caused  recording  engineers  endless 
difficulty  since  the  advent  of  sound  motion  pictures.  Many  attempts 
have  been  made  to  minimize  or  to  eliminate  this  noise,  but  so  far 
as  is  known,  none  of  the  remedies  heretofore  proposed  has  been  en- 
tirely successful.  Almost  all  the  studio  generator  equipment  is 
shunted  by  large  electrolytic  condensers,  and  in  a  few  instances 
several  turns  of  heavy  copper  cable  have  been  employed  as  an  air- 
core  inductance  in  series  with  the  load  circuit.  Such  air-core  induc- 
tances are  not  entirely  satisfactory,  however,  since  the  attainment  of 
sufficiently  high  values  of  inductance  is  usually  accompanied  by  the 
introduction  of  excessive  amounts  of  resistance  in  the  load  circuit. 

In  addition  to  the  overall  filtering  described  above,  it  has  been 
customary  to  employ  large  air-core  chokes,  each  having  a  current- 
carrying  capacity  of  approximately  1000  amperes,  on  each  set  utilizing 
arc  lamps.  Some  five  feet  in  diameter  and  weighing  approximately 
a  half-ton,  each  of  these  chokes  is  capable  of  providing  a  certain 
amount  of  filtering  to  a  load  consisting  of  eight  to  twelve  arc  lamps. 
These  chokes  are  commonly  mounted  on  dollies  so  that  they  may  be 
transported  from  set  to  set. 

*  Warner  Bros.  Pictures,  Inc.,  Burbank,  Calif. 

367 


368  B.  F.  MILLER  [j.  s.  M.  P.  E. 

Since  the  combined  filtering  provided  by  the  individual  chokes  on 
the  set  and  that  of  the  generator  filters  is  usually  insufficient  to  pre- 
vent audible  noise  from  the  arc  lamps,  additional  filtering  is  generally 
provided  for  each  lamp  in  the  form  of  small  iron-core  choke  coils  or 
"whistle-boxes,"  each  weighing  approximately  50  Ibs. 

Under  extremely  favorable  circumstances  this  filtering  combina- 
tion is  sufficient  to  eliminate  the  bulk  of  the  objectionable  singing 
noise  characteristic  of  arc-lamp  operation.  Under  more  adverse  con- 
ditions, however,  recordings  are  still  marred  by  arc-lamp  background 
noise.  A  further  reduction  in  lamp  noise  may  be  made  through 
first-class  maintenance  of  generator  equipment,  since  commutator 
ripple  magnitude  is  partially  determined  by  the  condition  of  gen- 
erator commutators  and  brushes.  However,  a  definite  lower  limit  of 
ripple  voltage  exists  for  each  generator  unit;  when  this  limit  has 
been  attained  the  remaining  necessary  reduction  in  ripple  voltage 
must  be  achieved  through  the  use  of  electrical  filtering  devices. 
Technicolor  productions  are  particularly  susceptible  to  lamp-noise 
trouble,  since  arc-lighting  is  used  almost  exclusively  for  color  photog- 
raphy. 

In  addition  to  the  fact  that  complete  suppression  of  lamp  noise  is 
extremely  difficult  with  the  type  of  filtering  described,  the  transporta- 
tion and  rigging  of  the  large  number  of  choke  coils  necessary  for 
each  operating  set  is  time-consuming  and  costly.  A  more  desirable 
form  of  filtering  would  therefore  provide  the  following  features : 

(1)  Complete  suppression  of  all  commutator  ripple  noise  from  arc 
lamps,  with  an  adequate  margin  of  safety  for  highly  variable  lamp 
loads  and  for  variations  in  magnitude  of  generator-ripple  voltage. 

(2)  A  single  filter  unit  which  could  be  permanently  associated  with 
a  lighting-generator  set. 

(3)  A  unit  whose  general  design  would   prove   adequate  for  a 
variety  of  generator  types. 

(4)  A  unit  which  would  provide  adequate  filtering  even  though  the 
generator  unit  with  which  it  was  associated  might  frequently  be  sub- 
jected to  moderate  overloading. 

(5)  An  essentially  compact  unit,  so  that  it  might  be  conveniently 
installed  adjacent  to  its  associated  generator. 

The  desirability  of  designing  a  unit  possessing  these  features  was 
recently  called  to  the  attention  of  the  writer  by  Mr.  Lee  Adams  of 
Warner  Bros.  Electrical  Department.  The  remainder  of  this  paper 
is  devoted  to  an  outline  of  the  unit  designed  and  a  brief  summary  of 


Nov.,  1943]  ARC-LIGHTING  GENERATOR  FILTER 

the  conclusions  reached  since  the  units  have  been  employed  in  pro- 
duction. 

A  number  of  noise-level  studies  were  first  made  on  typical  arc  lamps 
with  the  aid  of  a  General  Radio  sound-level  meter.  During  the  studies 
it  was  determined  that  arc-lamp  noise  would  be  reduced  to  a  negli- 
gible value  if  the  generator  ripple  was  reduced  by  a  factor  of  approxi- 
mately 30  decibels.  Oscillographic  studies  were  next  conducted  to 
determine  the  magnitude  and  frequency  distribution  of  the  principal 
ripple-voltage  components  present  in  the  generator  terminal  voltage. 
The  data  so  obtained  indicated  a  predominant  low-frequency  com- 
ponent of  approximately  900  cycles  per  second,  having  an  amplitude 
of  about  three  volts,  as  well  as  numerous  higher  frequency  compo- 
nents of  equal  or  lesser  magnitudes.  Tests  on  several  similar  generators 
indicated  that  the  data  obtained  from  the  first  unit  tested  might  be 
taken  as  typical. 

The  full-load  current  rating  of  the  generators  involved  was  1200 
amperes,  and  the  terminal  voltage  of  the  machines  was  120  volts. 
The  minimum  normal  load  impedance,  neglecting  any  inductance 
present  in  stage  feeder  circuits,  was  therefore  equal  to  0.10  ohm. 
After  some  consideration  it  was  decided  to  design  a  simple  "constant 
k"*  prototype  section  generator  filter  which  would  have  a  character- 
istic impedance  of  0.05  ohm  and  would  provide  a  minimum  of  40 
decibels  attenuation  to  the  lowest  frequency  ripple  component  pres- 
ent in  the  generator  terminal  voltage.  This  choice  was  based  upon 
the  following  grounds : 

(1)  Since  the  filter  would  be  terminated  in  a  highly  variable  load 
impedance,  the  variation  in  filtering  attained  would  be  minimized  if 
the  filter  characteristic  impedance  were  made  lower  than  the  lowest 
value  of  generator  load  impedance. 

(2)  Because  of  the  large  number  of  high-frequency  commutator 
ripple  components  present  at  the  generator  terminals,  it  was  necessary 
to  insure  that  adequate  filtering  would  be  provided  over  a  very  wide 
frequency  band ;  this  could  most  readily  be  accomplished  through  the 
use  of  prototype  filter  sections. 

*  Ed.  Note:  A  "constant  k"  type  filter  is  one  for  which  the  relation  ZiZ2  = 
k2  holds,  where  Z\  =  the  impedance  of  the  series  arm  and  Z2  =  the  impedance  of 
the  shunt  arm.  An  "Af-derived"  type  filter  is  one  in  which  the  image  impedances 
are  equal  to  those  of  a  "constant  k"  type  but  whose  configuration,  attenuation, 
and  phase  characteristics  are,  in  general,  different  from  those  of  the  constant  k 
type.  (See  "Transmission  Networks  and  Wave  Filters,"  T.  E.  Shea,  D.  Van 
Nostrand  Co.,  1929,  Chap.  VII.) 


370 


B.  F.  MILLER 


[J.  S.  M.  P.  E. 


(5)  The  incorporation  of  Jkf-derived  filter  sections  would  have 
necessitated  the  use  of  a  larger  number  of  filter  elements  and  would 
make  the  effectiveness  of  the  filter  somewhat  variable  with  different 
types  of  generator  equipment. 

A  preliminary  study  of  the  filter  requirements  led  to  the  conclusion 
that  the  most  economical  design  would  consist  of  one  and  one-half 
prototype  low-pass  sections,  having  a  cut-off  frequency  of  approxi- 
mately 400  cycles  per  second.  Upon  setting  the  filter  characteristic 
impedance  equal  to  Z0  and  the  filter  cut-off  frequency  equal  to  fc,  the 


0.0 £0 


0.040  MH. 


L, 

smtt< 

—                —  o 

PUT 

mm                                                    mm 

5                     OUT  PUT 

c, 

C2 

I5,ooo  r*fd. 

7,600    Mfd. 

FIG.  1. 

0.040    r"»H.                                    O.O40    r»7H. 

L, 

0000000 

+—                  —  o 

PUT                                  - 

•i                                                        tm 

2                     OUT  PUT 

c, 

C2 

15,000  rtftt. 

15,000    M^d 

>                              ft 

FIG.  2. 


required  inductance  L  and  capacitance  C  for  the  prototype  section 
were  determined  from  the  well  known  relationships : 


Upon  setting  Z0  =  0.05  and  fe  =  400,  the  required  value  of  L  be- 
comes equal  to  40  microhenries  and  that  of  C  equal  to  15,900  micro- 
farads. The  latter  value  was  actually  reduced  to  15,000  micro- 
farads, since  it  could  then  be  constructed  readily  by  employing  six 
2500-microf  arad  capacitor  banks. 

Employing  the  L  and  C  values  just  derived  the  filter  took  the  form 
shown  in  Fig.  1.  Calculations  of  the  core  size  required  for  the  filter 


Nov.,  1943]  ARC-LIGHTING  GENERATOR  FILTER  371 

inductances  were  next  carried  out  with  the  aid  of  formulas  previously 
derived  from  extended  studies  on  transformer  and  reactor  designs. 
From  these  it  was  determined  that  a  core  consisting  of  approximately 
113.5  Ibs  of  transformer  A  grade  silicon  steel  would  suffice  if  a  normal 
maximum  core  flux  density  of  10  kilogausses  was  employed.  Allowing 
a  normal  maximum  of  400  amperes  per  square  inch  of  winding  cross- 
sectional  area,  the  coil  copper  requirements  were  calculated  as  53.5 
Ibs. 


FIG.  3.       The  new- type  filtering  equipment  used 
on  a  set  requiring  5000  amperes. 

The  volume  of  iron  and  copper  required  for  the  40-microhenry  in- 
ductance was  considered  sufficiently  small  to  make  it  desirable  to 
employ  identical  inductances  in  both  filter  sections.  An  additional 
margin  in  the  amount  of  filtering  provided  could  also  be  obtained  at 
moderately  low  cost  by  employing  identical  capacitor  banks  at  both 
points  in  the  filter.  Accordingly,  the  initial  design  was  modified  to 
that  shown  in  Fig.  2.  This  unit  is  capable  of  producing  an  average 
of  approximately  50  decibels  attenuation  to  ripple  frequencies  of 
about  900  cycles  per  second  or,  roughly,  20  decibels  more  than  the 
amount  actually  required.  Higher  ripple  frequencies  are  attenuated 


372 


B.  F.  MILLER 


[J.  S.  M.  P.  E. 


in  a  somewhat  greater  degree.  Sufficient  copper  and  iron  are  pro- 
vided in  the  filter  inductances  so  that  overloads  of  fifty  per  cent  may 
be  tolerated  with  only  a  minor  reduction  in  the  degree  of  filtering 
attained. 

The  filter  inductances  as  finally  constructed  consist  of  a  single- 
turn  solid-cast  copper  winding  having  a  length  of  57  inches,  a  cross- 
section  of  3  square  inches,  a  weight  of  55  Ibs,  and  a  resistance  of 
0.00002  ohm.  The  core  consists  of  a  20-inch  stack  of  high-silicon  steel 
laminations  weighing  120  Ibs  and  is  provided  with  a  Vie-mch  ajr  gap 
to  satisfy  inductance  requirements.  When  the  coil  is  carrying  1200 


FIG.  4. 


The  old-type  filtering  equipment  used  on  a  set  requiring 
5000  amperes. 


amperes  d-c,  the  inductance  is  40  microhenries,  and  is  considerably 
higher  than  this  value  at  lower  values  of  load  currents.  The  full-load 
voltage  drop  across  the  inductance  is  approximately  25  millivolts 
which  is  negligible.  Normal  full-load  power  dissipation  in  the  coil 
winding  is  but  30  watts. 

The  experimental  filter  constructed  in  accordance  with  the  above 
design  proved  so  satisfactory  on  tests  that  a  sufficient  number  of 
additional  units  have  been  constructed  to  equip  every  fixed  and 
portable  generator  in  the  studio.  Since  these  installations  were  com- 
pleted not  a  single  case  of  trouble  from  arc-lamp  whistle  has  been  re- 
ported, and  the  filter  has  proved  satisfactory  even  when  carrying  an 
overload  of  1500  amperes.  Figs.  3  and  4  compare  the  new  and  old 
filtering  equipment  on  a  set  requiring  5000  amperes. 


Nov.,  1943]  ARC-LIGHTING  GENERATOR  FILTER  373 

The  advantages  and  economies  resulting  from  these  installations 
may  be  summarized  as  follows : 

(1)  The  filters  eliminate  all  commutator  ripple  noise  from  arc 
lamps. 

(2)  All  combination  and  individual  arc-lamp  chokes  are  eliminated, 
resulting  in  a  saving  of  time  on  the  sets,  a  saving  in  labor  formerly 
required  for  transporting  and  installing  the  chokes,   and  in  main- 
tenance costs  on  individual  chokes. 

(3)  The  filters  are  effective  at  all  values  of  load  current,  introduce 
no  appreciable  voltage  drop  in  the  load  circuit,  and  require  no  main- 
tenance of  any  kind. 

(4)  There  is  a  great  saving  in  cost  and  in  the  use  of  critical  mate- 
rials owing,  in  no  small  measure,  to  the  fact  that  the  new  filter  in- 
ductances require  only  one-fourteenth  as  much  copper  as  formerly  re- 
quired for  a  single  large-size  stage  choke  coil. 


ERRATUM 


In  the  October,  1943,  issue  of  the  JOURNAL,  Equation  (5)  on  p.  286  of  the 
paper  by  Ellsworth  D.  Cook  entitled  "The  General  Electric  Television  Film 
Projector,"  should  read  as  follows: 


NOTES  ON  THE  APPLICATION  OF  FINE-GRAIN  FILM  TO 
16-MM  MOTION  PICTURES* 

WM.  H.  OFFENHAUSER,  JR.** 

Summary.— In  September,  1939,  J.  A.  Maurer  reported  in  the  JOURNAL  on  "The 
Present  Technical  Status  of  16- Mm  Sound-Film"  and  in  November,  1940,  on  "Com- 
mercial Motion  Picture  Production  with  16-Mm  Equipment."  The  first  paper  com- 
pared the  quality  of  direct  16-mm  sound  with  that  of  reduction  prints  from  35-mm 
negatives;  the  second  compared  the  graininess  of  prints  by  the  reversal  (intermediate 
fine-grain  duplicate  negative)  fine-grain  print  method  with  reduction  prints  from  35- 
mm  original  negatives.  The  comparison  appeared  so  favorable  to  direct  16-mm  that 
the  next  step  was  obvious:  to  put  the  procedures  into  commercial  use. 

Early  experience  with  Dupont  fine- grain  materials  in  1930  and  1931  left  behind 
an  elementary  yet  important  consideration:  if  the  expected  improvements  from  the 
use  of  fine-grain  materials  and  methods  were  to  materialize,  something  more  than  the 
mere  use  of  fine-grain  materials  was  required.  Muck  in  developer,  fixer,  and  wash 
water  must  be  reduced;  films  must  be  properly  dried.  Only  with  these  elementary 
conditions  satisfied  could  the  quality  be  significantly  improved. 

Dupont  was  the  first  manufacturer  to  offer  fine-grain  release  print  film  to  the  16-mm 
market;  the  experience  with  Dupont  605  was  so  satisfactory  commercially  that  all 
ordinary  positive  materials  were  dropped  entirely.  Eastman  5203  was  found  to  be 
the  best  duplicate  negative  material  available;  all  other  materials  were  dropped.  For 
original  negatives  in  16-mm  direct  sound  recording,  Agfa  250,  a  high-resolving-power 
yellow-dye  film,  was  the  first  satisfactory  material  on  the  market  and  remained  without 
competitors  for  several  years.  With  such  excellent  materials  under  accurate  control, 
decidedly  improved  films  were  bound  to  result. 

It  is  interesting  to  note  that  these  present-day  materials  have  a  resolving  power  of 
the  order  of  100  lines  per  mm;  this  is  of  the  same  general  order  as  that  of  the  materials 
that  Dupont  produced  experimentally  in  1931.  While  resolving  power  of  this  order 
is  considered  sufficient  for  better-grade  present-day  projectors,  there  is  real  need  for 
pushing  the  quality  standard  still  farther  upward  to  150  lines  per  mm.  The  tech- 
niques for  the  manufacture  of  such  materials  are  fairly  well  known  today;  the  big  need 
is  for  Government  contracts  to  call  for  such  high-grade  materials  and  for  Government 
inspectors  rigidly  to  reject  inferior  materials  such  as  ordinary  positive  prints. 

The  selection  of  the  most  suitable  materials  and  the  manner  of  determining  the 
operating  conditions  for  the  machinery  selected  are  described. 

Introduction. — When  a  new  16-mm  print  is  removed  from  its  ship- 
ping container  for  the  first  time  and  placed  on  a  projector  for  its  first 
run  before  a  professional  audience,  there  is  a  momentary  silence;  the 

*  Presented  at  the  1943  Spring  Meeting  at  New  Yor  k. 
**  Precision  Film  Laboratories,  New  York. 

374 


APPLICATION  OF  FINE-GRAIN  FILM  375 

audience  evaluates  quickly  the  quality  of  the  projected  picture  and 
sound.  As  matters  stand  today,  a  user  has  no  way  of  knowing  before- 
hand just  what  the  quality  of  his  print  is  going  to  be;  there  is  no 
quality  standard  for  16-mm  prints. 

It  is  no  longer  true  that  the  output  of  16-mm  prints  is  so  small  and 
the  distribution  so  restricted  that  a  quality  standard  of  some  sort 
would  not  be  welcome.  With  millions  of  feet  of  film  pouring  out  of 
laboratories  each  week  at  Government  expense  and  with  user  groups 
varying  in  size  from  three  or  four  to  as  many  as  1000,  some  sort  of 
quality  measure  would  seem  sorely  needed. 

Standardization  of  16-Mm  Equipment. — For  some  time  we  have  had 
available  recommendations  concerning  the  16-mm  sound  projector; 
these  were  prepared  by  the  Non-Theatrical  Equipment  Committee  of 
the  Society  at  the  request  of  the  Committee  on  Scientific  Aids  to 
Learning,  of  the  National  Research  Council.  Armed  with  a  few  facts 
about  the  room  in  which  films  are  to  be  projected,  it  is  not  a  difficult 
matter  to  select  the  proper  size  and  type  of  screen  and  to  determine 
the  lumens  output  required  of  the  projector.  These  data  are  found  in 
the  Report  of  the  Non-Theatrical  Equipment  Committee  published 
in  the  July,  1941,  issue  of  the  JOURNAL. 

All  reputable  manufacturers  can  provide  certified  data  concerning 
each  type  of  machine  manufactured;  all  machines  of  a  particular  type 
are  guaranteed  to  perform  as  well  as  the  sample  machine  whose  per- 
formance has  been  certified.  With  the  ready  availability  of  such  in- 
formation and  performance  guarantees,  there  is  little  reason  today 
why  a  new  machine  (when  so  guaranteed)  should  not  be  well  suited 
to  its  intended  use. 

Quality  Status  of  16-Mm  Prints. — If  the  quality  status  of  16-mm 
prints  for  such  machines  is  investigated,  there  appears  to  be  no  dis- 
tinction between  a  print  suitable  for  an  audience  of  three  or  four  and  a 
print  suitable  for  1000 — unless  we  accept  the  term  "fine-grain."  The 
distinction  is  quite  vague;  we  use  the  term  "fine-grain"  for  the  higher- 
grade  film,  but  there  is  no  name  at  all — or  only  the  name  "ordinary 
print" — for  the  other.  There  is  no  precise  explanation  of  what  "fine- 
grain"  means  or  how  "fine"  a  fine-grain  film  must  be  to  be  suitable  for 
an  audience  of  1000. 

Quality  Status  of  35-Mm. — As  a  starting  point,  consider  the  quality 
of  the  projected  picture  and  sound  in  an  up-to-date  and  well-main- 
tained 35-mm  entertainment  theater  of  1000  seats.  Such  a  quality 
reference  is  reasonable;  it  is  a  convenient  reference  in  which  the  pic- 


376  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  P.  E. 

ture  is  of  good  quality  and  the  sound  is  of  good  quality.  The  standard 
is  commercially  feasible  yet  sufficiently  high  to  make  the  projected 
result  clearly  understandable  to  the  audience;  there  are  no  distrac- 
tions of  poor  quality  or  of  extraneous  noise  to  interfere  with  the  sub- 
ject matter  presented.  The  projection  equipment  of  the  reference 
theater  has  been  standardized  both  for  picture  projection  and  for 
sound  projection.  Equipment  is  as  carefully  designed  to  project 
sound  into  all  parts  of  the  audience  area  as  to  project  the  picture 
properly  into  that  area. 

Sixteen-mm  non -theatrical  equipment  has  not  yet  been  stand- 
ardized to  such  a  high  degree;  the  trend  seems  to  indicate  that  in  this 
respect  16-mm  will  follow  in  the  footsteps  of  its  larger  counterpart 
and  benefit  by  its  progress. 

Resolving  Power  Requirements. — The  raw  film  used  for  release  prints 
in  the  reference  35-mm  theater  is  ordinary  nitrate  positive;  such  film 
has  a  resolving  power  of  approximately  55  lines  per  mm.  (Eastman 
1301  and  Dupont  200  are  typical  ordinary  positive  materials.)  To 
obtain  equivalent  screen  definition  from  a  16-mm  material  would  re- 
quire greater  resolution  of  that  material  in  the  ratio  of  the  image 
areas;  or,  more  conveniently,  in  the  inverse  ratio  of  the  film  speeds; 
90/36  or  2J/2.  Fifty-five  lines  per  mm  multiplied  by  2x/2  equals  137V2 
lines  per  mm;  this  is  the  minimum  resolving  power  required.  It  is 
apparent  that  ordinary  positive  16-mm  materials  such  as  Eastman 
5301,  Dupont  600,  and  Agfa  220  are  woefully  inadequate;  materials 
of  far  higher  resolving  power  are  required  for  prints  that  are  compa- 
rable to  35-mm  in  quality. 

The  Resolving  Power  of  Available  Materials. — Eastman  Kodak  has 
recently  published  a  welcome  book,  "Properties  and  Performance  of 
Eastman  35-Mm  and  16-Mm  Films  for  Professional  Use."  This 
book  makes  it  convenient  to  choose  among  the  various  Eastman  ma- 
terials available.  If  we  rigidly  adhere  to  our  criterion  of  137V2  lines 
per  mm  and  expect  to  obtain  this  result  under  the  "average"  develop- 
ing conditions  therein  described,  there  is  but  one  Eastman  material 
available,  EK  5365,  which  has  sufficient  resolving  power;  the  value 
is  150  lines  per  mm.  Under  the  processing  conditions  specified,  this 
film  is  to  be  developed  for  9x/2  minutes  in  an  SD-21  developer  with  a 
lib  gamma  of  1.40.*  Table  I  shows  the  available  materials,  their 
suitability,  and  resolving  power. 

*  SD-21  is  the  equivalent  of  a  seasoned  or  partially  exhausted  D-76  metol- 
hydroquinone  negative  developer. 


Nov.,  1943] 


APPLICATION  OF  FINE-GRAIN  FILM 


377 


TABLE  I 
Available  Materials,  Their  Suitability,  and  Resolving  Power 


Material 

Rated 
Resolving 
Power 
(lines/mm) 

Eastman 

Dupont 

Agfa 

Ordinary  Positive 

55 
/     Not     \ 
Recom-    J 
\  mended  / 

No.  5301 
/      Not     \ 
1    Recom-    1 
\  mended  / 

No.  600 
1     Not    \ 
1   Recom-   J 
\  mended  / 

No.  220 
/     Not     \ 
1    Recom-    J 
\  mended  / 

Fine-grain 
Positive 

90 

No.  5302 
/      Satis-     \ 
1      factory     I 
\  Alternate  / 

No.  605 
(Preferred) 

Fine-grain 
Dupe  Negative 

110 

No.  5203 
(Preferred) 

Fine-grain 
Master  Positive 
(Yellow-dyed) 

150 

No.  5365* 
(Preferred) 

Sound-recording 
Negative 

No.  5557 
/     Not    \ 
1   Recom-  J 
\  mended  / 
No.  5372 
(Satis-    \ 
factory     J 
Alternate  / 

No.  602 
/     Not    \ 
1   Recom-  1 
\  mended  / 

No.  250 

(Preferred) 

Original  Picture 

75 

Kodachrome 
(Preferred) 

Cost  Factors— For  commercial  laboratory  use  at  the  present  time, 
the  selection  of  a  material  for  release  printing  that  would  require  a 
91/ 2- minute  developing  time  is  impracticable;  with  existing  equip- 
ment, the  average  laboratory  can  not  afford  a  developing  time 
greater  than  approximately  4  minutes.  If  we  add  the  additional 
cost  of  the  raw  film  (the  price  of  5365  is  higher  than  that  of  ordinary 
positive)  to  the  additional  processing  cost  (assuming  the  develop- 
ing time  of  ordinary  positive  to  be  2  to  3  minutes)  the  resulting  price 
would  represent  such  a  large  percentage  increase  that  some  very 
extensive  and  highly  expensive  persuasion  would  be  required  to  con- 
vince a  customer  (such  as  the  Government)  of  the  increase  in 
utility  that  would  justify  such  an  increase  in  price. 

Choice  of  Positive  Materials. — With  these  very  fundamental  limi- 
tations, it  is  apparent  that  the  choice  of  a  suitable  release  print  ma- 

*  Recommended  for  release  prints  because  of  fineness  of  grain  (when  developed 
in  a  negative  bath  that  is  low  in  bromide). 


378  W.  H.  OFFENHAUSER,  JR.  tf.  s.  M.  P.  E. 

terial  is  narrowed  down  to  a  fine-grain  positive  type  of  material  that 
can  be  developed  with  fine-grain  and  high-resolving-power  charac- 
teristics in  a  relatively  high-energy  developer  at  a  short  developing 
time.  Automatically  the  choice  rests  between  two  materials,  East- 
man 5302  and  Dupont  605.  In  either  case,  since  a  short  developing 
time  is  required,  a  developer  high  in  metol,  elon,  or  rhodol  (different 
trade  names  for  the  same  developing  agent)  is  required.  The  prac- 
tical choice  between  the  two  film  materials  will  be  dealt  with  later  in 
this  paper. 

Economics  of  Duplicate  Negatives. — When  the  subject  of  duplicate 
negatives  and  master  positives  is  considered,  the  economics  of  the 
problem  changes.  In  a  sense,  duplicate  negatives  and  master  posi- 
tives are  to  a  film  laboratory  what  special  production  tools  such  as 
automatic  lathes,  milling  machines,  drop  forge  presses,  special  jigs 
and  dies,  etc.,  are  to  a  factory.  The  automobile  industry  long  ago 
pointed  out  the  business  wisdom  of  buying  very  expensive  tools  for 
mass  production;  where  mass  production  of  prints  is  the  objective, 
it  would  seem  to  be  business  wisdom  to  make  the  best  duplicate  nega- 
tives and  master  positives  that  we  know  how.  If  we  have  a  genuine 
interest  in  quality,  the  problem  is  to  determine  what  is  the  best  dupli- 
cate negative  or  master  positive  with  little  regard  for  cost — and  to  go 
ahead  and  make  it. 

The  General  Method. — If  the  original  is  a  direct  16-mm  reversal  or 
Kodachrome,  the  best  black-and-white  release  prints  (all  things  con- 
sidered) that  can  be  made  in  quantity  are  made  by  the  duplicate 
negative-release  positive  print  method.  The  emulsion  position  of  the 
release  print  is  standard;  almost  all  sound  projectors  manufactured 
are  adjusted  to  proper  focus  of  sound  optics  for  this  emulsion  position. 
Sound  is  of  best  quality  by  this  method;  we  can  take  advantage  of 
the  distortion  cancellation  technique  that  is  practically  universal  for 
variable-area  film.  And  last  but  not  least,  the  contrast  of  the  picture 
can  be  nicely  controlled  to  produce  whatever  contrast  is  desired  in  the 
finished  print.  With  such  a  complement  of  advantages,  the  method 
may  be  considered  almost  ideal. 

Some  History  of  Fine-Grain  Film. — Before  going  into  the  procedure 
and  how  it  is  worked  out,  it  seems  appropriate  to  record  here  some  of 
the  unpublished  history  of  fine-grain  film  that  has  a  direct  bearing 
upon  the  materials  and  methods  now  employed.  In  1930  when  John 
A.  Maurer  was  working  on  a  sound-on-film  arrangement  called  "The 
Talking  Book,"  the  resolving  power  of  available  sound-recording 


Nov.,  1943]  APPLICATION  OF  FINE-GRAIN  FILM  379 

films  and  of  release  print  materials  was  poor  as  measured  by  present- 
day  standards.  In  a  variable-area  negative,  it  was  quite  a  feat  to 
record  5000  cps  on  35-mm  film  with  a  track  density  (unmodulated) 
of  1.5  and  a  fog  density  as  low  as  0.08;  many  of  us  would  have  felt 
overjoyed  if  we  could  keep  the  fog  density  consistently  below  0.06 
for  a  track  of  1.6  unmodulated  density.  We  had  no  special  films; 
release  positive  was  used  for  sound  negatives  as  well  as  for  release 
prints.  Fog  due  to  development  was  great  and  the  optical  systems 
commercially  used  produced  a  superabundance  of  stray  light. 

It  was  at  this  stage  of  the  art  that  Mr.  Oakley  of  Dupont  was  asked 
to  work  out  some  fine-grain  materials  for  the  talking-book  project. 
The  requirements  laid  down  were  as  unique  as  they  were  simple: 

"Use  every  precaution  to  keep  the  grain  fine — a  Lippman  type 
emulsion  is  the  sort  of  thing  we  need."  With  this  all-inclusive  re- 
quirement as  a  guide,  Drs.  V.  B.  Sease,  D.  R.  White,  and  others  of  the 
Dupont  research  group  quietly  went  to  work. 

The  details  of  the  work  are  too  long  to  report  here;  for  a  period  of 
a  year  or  more  Mr.  Maurer  made  recordings  every  week,  including  a 
number  of  recordings  of  Walter  Damrosch's  Musical  Appreciation 
Hour.  Often  during  the  year  the  author  listened  to  impromptu  re- 
corded concerts  when  we  would  compare  the  quality  of  the  older 
talking-book  recordings  with  that  of  the  newer  ones. 

The  quality  was  somewhat  better  than  the  best  disk  records  of  that 
time;  it  was  marred  far  more  by  the  microphonic  ping  of  the  224  tube 
in  one  of  the  low-level  amplifier  stages  than  by  any  "ground  noise" 
or  distortion  evident  in  the  speech  of  Dr.  Damrosch,  in  the  music  of 
his  illustrative  piano,  or  in  the  orchestral  performance  that  followed. 
The  recordings  as  reproduced  were  especially  free  of  noise  and  dis- 
tortion. 

What  is  especially  significant  is  that  these  recordings  utilized  film 
running  at  45  feet  per  minute  with  a  maximum  sound-track  width  of 
only  2  mils  as  compared  with  60  mils  for  standard  16-mm  tracks. 
There  were  more  than  300  sound-tracks  on  a  print  of  one  of  these 
films  that  the  writer  gave  to  Col.  M.  E.  Gillette  in  1934  for  his  sample 
collection. 

Experience  with  the  talking  book  sharply  accentuated  the  impor- 
tance of  fine-grain  film  and  its  processing.  In  a  special  series  of  fine- 
grain  tests  in  which  distilled  water  was  used  instead  of  water 
filtered  and  cleaned  in  the  manner  typical  of  commerical  laboratories 
at  the  time,  noise  was  reduced  some  10  db.  Even  today  a  reduction 


380  W.  H.  OFFENHAUSER,  JR.  [J.  S.  M.  P.  E. 

of  10  db  in  noise  is  something  to  be  sought  for;  if  water  cleanliness 
will  do  it,  every  effort  should  be  made  to  keep  the  water  clean.  (Dirty 
water  is  still  a  serious  problem  in  commercial  processing.) 

The  quality  of  the  talking-book  records  was  remarkable  for  the 
time;  most  commercial  laboratories  processing  16-mm  release  prints 
today  would  be  more  than  pleased  with  equal  quality.  Contemporary 
production  prints  do  not  yet  equal  those  old  records  in  quality;  the 
reason  for  the  technical  superiority  of  the  old  records  is  quite  simple; 
the  resolving  power  of  the  special  1931  film  was  100  to  110  lines  per 
millimeter,  about  double  that  of  the  ordinary  positive  used  by  most 
laboratories  today. 

Fine-Grain  Release-Print  Material:  Dupont  610. — With  such  a 
background  as  this,  it  was  only  logical  for  Precision  Film  Laboratories 
to  grasp  the  earliest  opportunity  to  use  fine-grain  materials  in  16-mm. 
When  Dupont  began  to  market  their  610  emulsion  several  years  ago, 
it  was  considered  most  desirable  to  adapt  the  methods  to  be 
used  to  the  available  material;  it  was  felt  that  commercial  benefit 
could  be  derived  from  the  excellent  basic  work  accomplished  in  1930 
and  1931.  Comparison  was  possible  only  between  Dupont  fine-grain 
610  and  ordinary  positive  materials  (there  were  no  other  fine-grain 
materials  on  the  market).  Within  a  year  after  the  first  trials  of  this 
material,  our  Laboratory  dropped  ordinary  positive  altogether  and 
has  processed  none  since. 

Dupont  605. — For  well  over  a  year  after  the  first  tests  with  Dupont 
610,  no  film  manufacturer  other  than  Dupont  offered  a  16-mm  fine- 
grain  release  print  material.  During  this  interval  the  film  was  being 
constantly  improved,  and  later  Dupont  605  was  evolved.  This  new 
material  proved  even  better  than  its  predecessor  and,  since  its  ad- 
vantages were  outstanding,  our  Laboratory  standardized  on  it  as  the 
one  and  only  raw  film  for  release  print  purposes. 

Today's  Status — Conditions  of  Use. — For  procedure  simplification 
and  for  best  quality  and  maximal  uniformity  of  product,  our  Labora- 
tory still  uses  one  release  positive  material:  Dupont  605.  This  ma- 
terial satisfies  the  commercial  requirements  with  regard  to  operating 
costs,  and,  in  addition,  to  such  technical  requirements  as  image  tone, 
photographic  scale,  resolving  power,  and  graininess,  as  well  as  a  very 
desirable  hardness  of  emulsion  that  makes  "protective  coatings"  and 
similar  treatment  unnecessary  for  prints  projected  in  machines  that 
are  kept  in  good  repair. 

To  get  the  most  out  of  this  excellent  fine-gram  release  print  ma- 


Nov.,  1943]  APPLICATION  OF  FINE-GRAIN  FILM  381 

terial,  all  release  prints  are  developed  at  one  developing  time.  All 
printers  are  of  the  step-contact  type;  these  seem  to  give  best  image 
definition.  For  uniformity,  all  printers  are  of  the  same  type;  all  use 
the  same  type  of  lamp  as  a  light-source,  all  run  at  the  same  speed,  and 
all  will  print  any  dupe  negative  (made  in  our  Laboratory)  on  the 
same  single  printer  light.  Within  the  past  two  years  we  have  found  no 
outstanding  attributes  of  any  other  fine-grain  release  positive  ma- 
terials to  justify  altering  this  procedure. 

In  practice,  only  the  compensations  for  the  batch-to-batch  varia- 
tions of  sensitometric  characteristics  are  necessary  to  keep  the  process 
well  under  control.  To  develop  this  fine-grain  film  properly  necessi- 
tated an  increase  in  developer  concentration  of  about  one-third  together 
with  an  increase  in  rhodol  (the  increase  is  more  than  two  to  one)  and 
a  reduction  in  the  bromide  of  about  one- third.  The  reference  formula 
is  the  Eastman  D-16. 

With  the  experience  of  1931  in  regard  to  the  talking-book  project 
in  mind,  special  pains  are  taken  to  filter  and  clean  all  water,  to  main- 
tain temperature  control,  and  last  but  not  least,  to  control  the  clean- 
liness, the  humidity,  and  the  temperature  of  the  drybox  air.  It  would 
seem  futile  to  go  through  all  the  motions  of  control  that  have  been 
indicated,  and  then  spoil  the  good  work  by  imbedding  muck  from 
dirty  chemical  baths  or  wash  water,  and  by  forcibly  blowing  dust  and 
other  dirt  particles  right  into  the  emulsion  during  the  drying  process. 
A  10-db  reduction  in  noise  which  can  be  achieved  by  cleanliness  is 
well  worth  striving  to  obtain.  As  has  been  explained  in  some  detail 
in  a  previous  paper,1  great  care  and  attention  are  given  to  proper  fixing 
and  drying.  Film  may  be  taken  directly  from  the  developing  machine 
take-up  for  immediate  projection  on  the  Bell  &  Howell  Utility  pro- 
jectors that  are  used  for  inspection.  No  "preservative"  is  needed  to 
"ease"  the  film  through  the  projector;  the  film  is  not  "green." 

The  Duplicate  Negative. — The  positive  print  is  held  within  quite 
narrow  sensitometric  limits;  these  limits  are  predetermined  by  the 
characteristics  of  the  film  itself,  by  the  developing  machine,  and  by 
the  machinery  used  to  expose  the  film.  To  produce  a  release  print  in 
the  manner  described  requires  an  "evened-out"  duplicate  negative 
that  is  quite  uniform;  the  characteristics  of  this  duplicate  negative 
are  the  key  to  the  methods  employed. 

As  in  the  case  of  the  release  positive  material,  the  first  step  is  to 
select  the  one  most  desirable  duplicate  negative  raw  film;  the  ma- 
terial with  the  highest  resolving  power  and  the  most  suitable  scale 


382  W.  H.  OFFENHAUSER,  JR.  tf.  s.  M.  P.  E. 

and  gamma.  In  this  case  the  choice  was  Eastman  5203.  The  rated 
resolving  power  is  110  lines  per  mm  in  an  SD-21  developer  at  a 
lib  control  gamma  of  0.65  (which  represents  a  developing  time  of  6 
minutes).  To  make  fine-grain  prints  of  proper  contrast  from  re- 
versal or  Kodachrome  originals  with  this  material  for  the  inter- 
mediate duplicate  negative  requires  a  smaller  lib  control  gamma 
(under  our  conditions)  than  is  specified  in  the  Eastman  data.  The 
first  step  was  to  determine  what  the  control  gamma  should  be  for 
an  "average"  reversal  or  Kodachrome  and  to  make  adjustments  in 
the  developer  bath  and  elsewhere  so  that  our  regular  step-contact 
printers  with  their  20-light  scales  may  be  used  in  making  these  dupe 
negatives.  As  before,  the  machines  were  the  same,  the  lamps  were 
the  same;  obviously  the  juggling  had  to  be  done  with  the  de- 
veloper bath.  We  made  one  slight  change;  since  there  was  plenty 
of  exposure  available,  a  filter  was  introduced  to  limit  the  exposing 
light  to  wavelengths  shorter  than  5000  Angstroms.  This  helped  to 
reduce  the  contrast  and  improve  the  definition  and  graininess  of  the 
dupe  negative.  (EK  5203  is  panchromatic.) 

Timing. — We  had  observed  in  printing  a  black-and-white  duplicate 
negative  from  a  Kodachrome  original,  that  the  timing  was  quite 
similar  to  that  used  in  printing  a  Kodachrome  duplicate  from  the 
same  original.  If  the  contrast  of  the  finished  products  were  supposed 
to  be  the  same,  there  would  seem  to  be  little  reason  why  it  should  not 
be  possible  to  make  the  timing  of  them  identical.  This  proved  to  be 
practicable  as  a  commercial  procedure ;  today  the  timing  of  a  Koda- 
chrome original  for  black-and-white  prints  is  identical  to  its  timing 
for  Kodachrome  duplicates.  When  this  procedure  was  first  tried 
commercially,  slight  readjustments  in  dupe  negative  developing  were 
required.  It  may  be  interesting  to  know  that  the  developer  bath 
for  duplicate  negatives  is  used  also  for  original  negative;  the  only 
difference  is  an  appreciably  longer  developing  time  for  original 
negative.  The  amount  of  16-mm  negative  in  use  is  very  small; 
negative  is  not  used  today  in  any  project  where  a  large  number  of 
prints  is  required. 

Developing  the  Dupe  Negative. — The  bath  for  the  dupe  negative 
is  such  as  to  produce  the  desired  gamma  with  a  developing  time  of  3 
to  4  minutes.  The  lib  control  gamma  for  EK  5203  under  our  condi- 
tions is  in  the  range  0.35  to  0.40,  slightly  lower  than  that  of  usual 
developers.  Accurate  sensitometric  control  is  a  "must";  experience 
over  a  long  period  points  out  quite  forcibly  that  no  timer  can  properly 


Nov.,  1943]  APPLICATION  OF  FINE-GRAIN  FILM  383 

time  a  film  for  printing  unless  the  process  is  well  "tied  down."  When 
we  first  tried  to  make  prints  from  dupe  negatives,  it  did  not  take  long 
to  recognize  that  timing  a  duplicate  negative  for  a  print  usually 
resulted  in  a  poorer  print  than  a  one-light  print  from  the  same  dupe 
negative.  Obviously  the  error  was  in  making  the  dupe  negative  from 
the  original;  the  proper  correction  of  the  error  is  correction  at  the 
source:  a  new  dupe  negative.  The  resulting  technique — with  all 
timing  in  making  the  dupe  negative  and  one-light  printing  of  the 
dupe  for  making  the  release  prints — would  seem  to  be  almost  ideal 
for  making  highest-quality  fine-grain  black-and-white  prints  in  large 
quantity  with  greatest  uniformity. 

16-Mm  Prints  from  35-Mm  Negatives. — When  it  is  necessary  to 
make  good  fine-grain  16-mm  prints  from  35-mm  negatives,  our 
Laboratory  prefers  a  low  positive  gamma  (1.40)  yellow-dyed  fine- 
grain  untimed  35-mm  master  positive  on  such  film  as  Eastman  1365; 
the  one-light  master  positive  is  actually  much  better  than  the  usual 
mis-timed  copy.  It  so  happens  that  such  a  master  positive  may  be 
timed  in  our  plant  in  making  a  16-mm  dupe  negative  in  exactly  the 
same  way  and  using  the  identical  timing  scale  as  that  for  Koda- 
chrome  or  reversal  16-mm  originals.  Black-and-white  fine-grain 
release  prints  made  in  this  way  result  in  excellent  gradation,  really 
fine-grain,  and  a  definition  and  softness  that  is  unknown  in  direct 
reduction  printing  from  35-mm  original  negatives.  (Step  picture 
printing  is  used  throughout.) 

Most  commercial  reduction  printers  run  at  too  high  speed  to 
provide  sufficient  exposure  for  fine-grain  film;  if  these  printers  are 
slowed  down  to  speeds  that  will  provide  adequate  exposure,  the 
resulting  print  is  too  contrasty  for  usual  positive  developers.  For 
direct  reduction  printing  on  fine-grain  ]  6-mm  films,  35-mm  original 
picture  negatives  are  made  to  far-too-high  gammas  for  successful  use. 

SOUND 

So  far  this  paper  has  dealt  only  with  the  picture  phase  of  the 
printing  problem;  a  paper  that  would  do  justice  to  the  subject  must 
emphasize  sound  for  the  reason  that  sound  can  be  said  to  have 
started  it  all.  To  acquire  the  proper  perspective,  it  is  necessary  to 
digress  somewhat  in  considering  the  subject.  It  is  a  well  known 
experimental  design  trick  for  an  investigator  to  make  scale  models 
of  the  device  he  is  studying.  If  the  device  is  something  big  such  as 
a  Mars  flying  boat  or  a  new  super-dreadnaught,  he  makes  small 


384  W.  H.  OFFENHAUSER,  JR.  [J.  S.  M.  P.  E. 

models  that  are  convenient  to  study  in  a  miniature  wind-tunnel  or 
test-tank.  If  the  device  is  something  small  such  as  a  high-quality 
cutter  for  disk  records,  he  makes  large  models  so  that  the  action  of 
the  various  moving  members  may  be  studied  in  more  convenient 
fashion.  Knowing  the  characteristics  of  the  system  under  investi- 
gation, it  is  possible  to  predict  the  performance  of  the  full-scale 
device  from  the  knowledge  of  the  performance  of  the  made-to-scale 
model. 

In  a  sense,  the  fine-grain  application  problem  was  similar  in  its 
first  approximations  especially.  If  35-mm  could  tolerate  a  resolving 
power  of  so  many  lines  per  mm,  16-mm  would  require  2l/2  times  that 
figure.  If  35-mm  could  tolerate  so  many  pounds  of  muck  per  million 
gallons  of  water,  16-mm  could  tolerate  not  more  than  1/&6  that 
amount.  If  35-mm  could  tolerate  so  many  pounds  of  dirt  per  million 
cubic  feet  of  air  used  for  drying,  16-mm  could  tolerate  not  more  than 
1/z.&  that  amount.  This  proved  a  good  starting  point. 

The  16-Mm  Sound  Negative. — As  in  all  cases  of  proportional  scalar 
design,  non-linear  relationships  were  found:  in  simpler  language, 
"bugs."  One  of  the  worst  of  these  was  the  poor  resolving  power 
of  film  materials  used  for  35-mm  sound  recording.  The  resolving 
power  available  was  too  low  for  16-mm;  only  x/2.5  the  proportional 
requirement.  There  was  little  hope  in  conventional  films;  sub- 
stantial increases  in  resolving  power  resulted  in  requirements  of 
exposure  considerably  beyond  what  could  be  hoped  for  in  the  exposing 
ability  of  a  6-volt  1 -ampere  lamp.  At  our  request,  Agfa  made  a 
yellow-dyed  film  (now  known  commercially  as  Agfa  type  250  high- 
resolving-power  sound-recording  film)  which  worked  quite  well 
when  exposed  through  a  Jena  BG-12  filter.2  The  harmonic  distortion 
in  the  negative  was  reduced  far  below  that  in  the  usual  35-mm  ultra- 
violet stocks  with  ultraviolet  exposure;  in  a  variable-area  negative 
of  density  1.5,  for  instance,  the  harmonic  distortion  of  an  85  per  cent 
modulated  400-cycle  wave  was  under  1  per  cent,  whereas  a  distortion 
of  about  8  per  cent  was  common  in  16-mm  ultraviolet  negatives. 
It  is  well  to  point  out  that  for  more  than  three  years  no  competitor 
attempted  to  market  a  comparable  film ;  it  appeared  that  no  competi- 
tor thought  it  worth  while. 

Commercial  production  experience  with  Agfa  250  for  16-mm 
sound  negatives  and  Dupont  605  for  release  prints  (variable-area 
recording)  produced  a  series  of  incidents  indicating  that  further 
progress  would  have  to  be  made  without  any  further  attempt  to  rely 


Nov.,  1943]  APPLICATION  OF  FINE-GRAIN  FILM  385 

on  previous  35-mm  experience.  Prints  of  400-cycle  85  per  cent 
modulated  recordings  were  possible  with  quite  consistent  rms  har- 
monic distortion  less  than  2  per  cent.  Intermediation  tests  of 
6000 — 400  cycles  and  4000 — 400  cycles  gave  strange  results  when 
checked  with  the  harmonic  distortion  results.  It  appeared  that  we 
had  run  into  a  new  breed  of  "bug"  with  which  the  industry  seems 
to  have  had  no  previous  experience. 

One  odd  phenomenon  of  this  new  breed  is  worth  mentioning. 
Suppose  that  a  conventional  sound  negative  is  recorded  in  which 
there  is  a  voice  together  with  a  musical  background.  By  making 
a  print  in  one  manner,  the  subjective  level  of  the  music  is  raised 
with  respect  to  the  voice;  by  making  a  print  in  another  manner, 
the  subjective  level  of  the  music  is  lowered  with  respect  to  the 
voice.  Both  prints,  when  compared,  are  quite  "clean"  by  today's 
highest  commercial  standards,  yet  the  difference  in  subjective  level 
of  the  music  referred  to  that  of  the  voice  seems  as  much  as  10  db  in 
the  two  prints.  If  this  phenomenon  were  to  occur  in  Hollywood, 
it  would  certainly  lead  to  much  disagreement  between  a  re-recording 
mixer  man  and  the  director  if  either  should  depend  upon  the  sound 
from  the  monitor  horn  at  the  time  the  take  was  actually  made. 

This  phenomenon  has  its  caution  lights;  the  character  of  the  dis- 
tortion is  audibly  different  in  one  kind  of  print  from  that  in  the  other. 
Unfortunately  we  have  found  no  magic  formula  to  provide  an  un- 
equivocal answer  as  to  how  a  print  shall  be  processed;  neither  inter- 
modulation  nor  harmonic  distortion  tests  alone  are  reliable.  As 
George  Friedl  used  to  phrase  it  at  our  Standards  Committee  meet- 
ings, "It  is  a  matter  of  how  we  prefer  to  have  our  sound  distorted." 

A  common  characteristic  of  distortion  in  improperly  processed 
35-mm  variable-density  prints  is  harmonic  distortion,  yet  with  16-mm 
fine-grain  variable-density  prints  we  have  encountered  some  out- 
standing examples  of  whistling  sibilant  distortion  that  are  ordinarily 
associated  with  variable-area  records.  Similarly,  while  the  common 
distortion  characteristic  of  variable-area  35-mm  records  that  are 
improperly  processed  is  envelope  distortion,  we  have  encountered 
some  outstanding  examples  of  raspiness  due  to  harmonic  distortion 
with  little  evidence  of  envelope  distortion.  With  the  materials 
described  in  this  paper,  however,  both  envelope  distortion  and 
harmonic  distortion  are  at  a  minimum,  and  are  somewhat  below  the 
distortion  levels  in  current  35-mm  feature  prints  released  to  theaters. 

It  is  no  longer  possible  to  classify  a  sound  recording  as  variable- 


386  W.  H.  OFFENHAUSER,  JR.  [j.  s.  M.  P.  E. 

area  or  as  variable-density  merely  by  the  character  of  the  most 
apparent  audible  distortion.  If  noise  levels  and  distortion  levels 
are  to  be  further  reduced,  as  they  should  be  in  the  near  future,  new 
techniques  will  have  to  be  evolved;  they  may  take  into  account  even 
the  character  of  the  sound  to  be  recorded.  It  is  no  longer  possible 
to  specify  the  optimal  density  of  a  print  from  a  sound  negative  by 
merely  applying  a  rule  of  thumb ;  a  specification  that  requires  such 
material  or  a  laboratory  that  produces  it  will  soon  show  all  too 
plainly  that  the  industry  has  been  accelerating  rapidly  out  of  the 
rule-of-thumb  era. 

16-Mm  Sound  Negative  Materials. — Within  the  past  year,  Eastman 
Kodak  has  released  EK  5372,  a  blue-dyed  film  which  is  functionally 
similar  to  Agfa  250.  EK  5372  is  definitely  "faster"  than  Agfa  250 
when  exposed  in  a  Maurer  16-mm  sound  recorder.  For  that  reason 
it  is  convenient  to  use,  but  sufficient  data  are  not  yet  available  to 
determine  whether  the  increase  in  speed  is  not  gained  at  the  expense 
of  too  great  a  loss  of  resolving  power.  For  ordinary  purposes,  the 
practical  differences  do  not  seem  large. 

Conclusion. — In  the  earlier  part  of  this  paper,  it  was  pointed  out 
that  a  desirable  "ideal"  would  be  to  use  materials  of  resolving  power 
of  I37l/z  lines  per  mm  or  greater.  Under  practical  conditions  of 
operation,  it  is  likely  that  our  Laboratory  approaches  this  figure 
with  the  duplicate  negatives.  The  release-print  material  falls  some- 
what short,  although  the  conditions  realized  in  practice  are  better 
than  the  published  data.  These  materials  and  the  technique  of 
handling  them  result  in  16-mm  print  quality  of  the  very  highest 
commercial  standards.  Film  processed  in  this  manner  is  more  than 
adequate  for  picture  projection  with  the  best  16-mm  lenses  in  the 
best  16-mm  projectors.  With  regard  to  sound,  the  significant 
improvement  resulting  from  the  engineered  use  of  fine-grain  materials 
is  not  so  much  the  extension  of  the  frequency  range  (together  with 
the  reduction  in  noise,  hush-hush,  and  other  equally  obvious  and 
readily  recognized  factors)  as  the  reduction  of  distortion  to  levels 
far  below  those  expected  from  "scale-model"  considerations  of  35-mm 
apparatus  and  materials. 

There  is  plenty  of  work  to  be  done  to  boost  the  quality  level  of  an 
"average"  16-mm  performance.  Today  we  are  using  film  materials 
whose  resolving  power  is  comparable  with  that  of  the  lenses  of  better- 
grade  projectors :  80  lines  per  mm.  Already  there  has  been  signifi- 
cant clamor  for  revision  of  this  figure  upward  although  it  was  con- 


Nov.,  1943]  APPLICATION  OF  FINE-GRAIN  FILM  387 

sidered  satisfactory  only  a  year  and  a  half  ago.  Materials  with 
resolving  power  of  100  lines  per  mm  were  available  in  1931; 
150-lines-per-mm  material  is  available  now.  The  technique  of 
manufacture  of  the  latter  material  is  fairly  well  known ;  the  problem 
is  to  prepare  to  process  this  material  commercially  and  to  bring  the 
price  to  lower  levels  by  making  the  use  of  such  material  the  rule 
rather  than  the  exception.  This,  it  seems,  is  the  next  hurdle  for 
progressive  laboratories  to  jump  regardless  of  whether  they  process 
100,000  feet  or  100,000,000  feet  per  year. 

Good  film  can  be  obtained  now;  the  film  manufacturers  are 
prepared  to  help  any  laboratory  that  is  interested  by  providing  in- 
formation as  to  the  highest-resolving-power  materials  they  sell  and 
the  manner  of  effectively  using  them.  The  major  step  that  is 
missing,  and  which  can  be  readily  taken  if  there  is  a  serious  and 
honest  interest  in  quality,  is  the  requirement  in  all  Government 
specifications  that  any  release  print  will  be  rejected  if  in  test  under 
actual  conditions  of  use  it  shows  less  than  100  lines  per  mm;  any 
duplicate  negative  will  be  rejected  if  in  test  under  actual  conditions 
it  shows  less  than  110  lines  per  mm;  and  any  master  positive  will  be 
rejected  if  in  test  under  actual  conditions  it  shows  less  than  150  lines 
per  mm.  Any  test  to  be  valid  shall  be  a  continuous  part  of  the  film 
under  test;  it  shall  not  be  removed  from  the  film.  Rejection  shall 
result  without  further  inspection  if  the  specified  test-strip  does  not 
appear  on  the  end  of  each  film. 

These  requirements  on  resolving  power  will  make  an  excellent 
starting  point;  once  they  have  been  included  in  specifications,  and 
rigid  and  thorough  100  per  cent  inspection  is  instituted  to  assure  that 
the  specification  is  being  met,  the  big  step  in  the  direction  of  quality 
for  16-mm  release  prints  will  have  been  taken. 

REFERENCES 

1  OFFENHAUSER,  W.  H.,  JR.:  "The  16-Mm  Commercial  Film  Laboratory," 
J.  Soc.  Mot.  Pict.  Eng.,  XLI  (Aug.,  1943),  p.  157. 

*MAURER,  J.  A.:  "The  Present  Technical  Status  of  16-Mm  Sound-Film," 
/.  Soc.  Mot.  Pict.  Eng.,  XXXIII  (Sept.,  1939),  p.  315. 

8  OFFENHAUSER,  W.  H.,  JR.,  AND  HARGROVE,  F.  H.:  "Some  Industrial  Ap- 
plications of  Current  16-Mm  Sound  Motion  Picture  Equipment,"  /.  Soc.  Mot. 
Pict.  Eng.,  XXXIV  (Feb.,  1940),  p:  156. 

4  Report  of  the  Committee  on  Non-Theatrical  Equipment:  "Recommended 
Procedure  and  Equipment  Specifications  for  Educational  16-Mm  Projection," 
J.  Soc.  Mot.  Pict.  Eng.,  XXXVH  (July,  1941),  p.  22. 


388  W.  H.  OFFENHAUSER,  JR. 

*  STEPHENS,  R.  E.,  "Optical  and  Mechanical  Characteristics  of  16-Mm  Mo- 
tion Picture  Projectors,"  Bur.  Stand.  Circular  C437  (June,  1942). 

•  SNYDER,  W.  F.,  "Acoustic  Performance  of  16-Mm  Sound  Motion  Picture 
Projectors,"  Bur.  Stand.  Circular  C439  (July,  1942). 

7  OFFENHAUSER,  W.  H.,  JR.:  "A  Review  of  the  Question  of  16-Mm  Emulsion 
Position,"  /.  Soc.  Mot.  Pict.  Eng.,  XXXIX  (Aug.,  1942),  p.  130. 

8  "Eastman  Motion  Picture  Films  for  Professional  Use,"  Eastman  Kodak 
Company  (Rochester,  N.  Y.),  1942. 

9  MAURER,  J.  A.:     "Commercial  Motion  Picture  Production  with  16-Mm 
Equipment,"  /.  Soc.  Mot.  Pict.  Eng.,  XXXV  (Nov.,  1940),  p.  437. 

10  OLSON,  H.  F.:  "Extending  the  Range  of  Acoustic  Reproducers,"  Proc.  Radio 
Club  of  Am.,  Vol.  18,  No.  1  (Jan.  1941). 


PLANNING  FOR  16-MM  PRODUCTION* 
RUSSELL  C.  HOLSLAG** 


Summary. — The  paper  discusses  production  of  16-mm  "expository"  films — those 
which  explain  or  instruct.  The  most  important  factor  involved  is  the  advance  plan- 
ning of  an  adequate  presentation  of  the  subject  matter.  A  direct,  simple  method  of 
production  planning  has  been  evolved  and  is  described,  pointing  out  pitfalls  which  the 
beginner  should  avoid.  A  shooting-script  form,  which  serves  the  producer  as  a  com- 
bined scenario,  shooting  script,  and  editing  reference,  is  described  and  illustrated. 
Experience  indicates  that  the  teacher  or  expert  who  is  to  guide  the  production  of  a 
training  film  should  give  his  particular  attention  to  building  up  a  concept;  avoiding 
overextended  commentation;  having  the  visual  demonstration  coincide  with  the  sound- 
track explanation;  showing  no  action  that  is  unexplained,  or  no  explanation  un- 
accompanied by  action;  timing  the  delivery  of  the  commentation;  using  the  full  power 
of  the  camera;  and  to  treating  the  audience  as  an  individual  novice  about  to  receive 
instructions  through  motion  pictures. 

T